Opportunity Mars Rover mission: Overview and selected results from Purgatory ripple to traverses to Endeavour crater

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Citation Arvidson, R. E., J. W. Ashley, J. F. Bell, M. Chojnacki, J. Cohen, T. E. Economou, W. H. Farrand, et al. 2011. “Opportunity Mars Rover Mission: Overview and Selected Results from Purgatory Ripple to Traverses to Endeavour Crater.” Journal of Geophysical Research 116, no. E7.

Published Version doi:10.1029/2010JE003746

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Opportunity Mars Rover Mission: Overview and Selected Results from Purgatory Ripple to Traverses to Endeavour Crater

R. E. Arvidson1, J. W. Ashley2, J.F. Bell III3, M. Chojnacki4, J. Cohen5, T. E. Economou6, W. H. Farrand7, R. Fergason8, I. Fleischer9, P. Geissler8, R. Gellert10, M. P. Golombek11, J. P. Grotzinger12, E. A. Guinness1, R. M. Haberle13, K. E. Herkenhoff8, J. A. Herman11, K. D. Iagnemma14, B. L. Jolliff1, J. R. Johnson8, G. Klingelhöfer9, A.H. Knoll15, A. T. Knudson16, R. Li17, S. M. McLennan18, D. W. Mittlefehldt19, R.V. Morris19, T. J. Parker11, M. S. Rice3, C. Schröder20, L. A. Soderblom8, S. W. Squyres3, R. J. Sullivan3, M. J. Wolff7

1 Dept. of Earth and Planetary Sciences, Washington University, St. Louis, MO, USA 2School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA 3Dept. of Astronomy, Cornell University, Ithaca, NY, USA 4Planetary Geosciences Institute, Dept. of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN, USA 5Honeybee Robotics Spacecraft Mechanisms Corporation, New York, New York, USA. 6Laboratory for Astrophysics and Space Research, Enrico Fermi Institute, University of Chicago, Chicago, IL, USA 7Space Science Institute, Boulder, CO, USA 8U.S. Geological Survey, Flagstaff, AZ, USA

9Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany 10Dept. of Physics, University of Guelph, Guelph, ON, N1G 2W1, CANADA 11Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA 12 Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA 13NASA Ames Research Center, Moffett Field, CA, USA 14Dept. of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA 15Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA 16Planetary Science Institute, Tucson, AZ, USA 17Dept. of Civil & Env. Eng. & Geodetic Science, Ohio State University, Columbus, OH, USA 18Department of Geosciences, State University of New York at Stony Brook, Stony Brook, NY, USA 19NASA Johnson Space Center, Houston, TX, USA 20University of Bayreuth and Eberhard Karls University of Tübingen, Center for Applied Geoscience, Tübingen, Germany

Submitted to: JGR-Planets, MER Special Issue

Revision Submitted 11/3/10 1

1 Abstract

2 Opportunity has been traversing the Meridiani plains since 1/25/2004 (sol 1),

3 acquiring numerous observations of the atmosphere, soils, and rocks. This paper provides

4 an overview of key discoveries between sols 511 and 2300, complementing earlier papers

5 covering results from the initial phases of the mission. Key new results include: 1.

6 Atmospheric argon measurements that demonstrate the importance of atmospheric

7 transport to and from the winter carbon dioxide polar ice caps. 2. Observations showing

8 that aeolian ripples covering the plains were generated by easterly winds during an epoch

9 with enhanced Hadley cell circulation. 3. The discovery and characterization of cobbles

10 and boulders that include iron and stony-iron meteorites and Martian impact ejecta. 4.

11 Measurements of wall rock strata within Erebus and Victoria craters that provide

12 compelling evidence of formation by aeolian sand deposition, with local reworking

13 within ephemeral lakes. 5. Determination that the stratigraphy exposed in the walls of

14 Victoria and Endurance craters show an enrichment of chlorine and depletion of

15 magnesium and sulfur with increasing depth. This result implies that regional-scale

16 aqueous alteration took place before formation of these craters. Most recently,

17 Opportunity has been traversing toward the ancient Endeavour crater. Orbital data show

18 that clay minerals are exposed on its rim. Hydrated sulfate minerals are exposed in plains

19 rocks adjacent to the rim, unlike the anhydrous surfaces of plains outcrops observed thus

20 far by Opportunity. With continued mechanical health, Opportunity will reach terrains on

21 and around Endeavour’s rim that will be markedly different from anything examined to

22 date.

23 2

24 Introduction

25 The Mars Exploration Rover (MER) Opportunity touched down on the Meridiani

26 plains on January 25, 2004 (Figs. 1-2). Since landing, Opportunity has conducted

27 numerous traverses and made extensive measurements with its Athena science payload

28 (Table 1), including examination of impact crater ejecta deposits, rims, and walls to

29 access and characterize stratigraphic rock sections within the Burns formation [e.g.,

30 Squyres and Knoll, 2005], detailed examination of a variety of cobbles and boulders

31 exposed on the surface, and characterization of the aeolian ripples that partially cover

32 plains outcrops. In addition, numerous atmospheric opacity and cloud measurements have

33 been acquired using Pancam and Navcam, and the Alpha Particle X-Ray Spectrometer

34 (APXS) has been used to monitor atmospheric argon mixing ratios.

35 The purpose of this paper is to summarize operations and present selected

36 scientific highlights from the time Opportunity left the Purgatory* aeolian ripple on sol

37 511 (July 1, 2005) to the first relatively high spatial resolution views of the Endeavour

38 crater rim on sol 2300 (July 13, 2010; Fig.1 and Table 2). The paper also includes a

39 synthesis of orbital and rover-based data for areas along and close to Opportunity’s

40 traverses for interpretations of material properties, morphology, and geologic histories on

41 both local and regional scales. This overview is meant to complement papers that provide

42 detailed findings from Opportunity’s measurements that are included as the fourth set of

43 Mars Exploration Rover papers published in the Journal of Geophysical Research and

44 also published elsewhere over the past several years. For reference, Squyres et al., [2003]

45 provide a summary of the Athena science payload and Squyres et al., [2006] summarize

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46 Opportunity mission results up to embedding into and extrication from the Purgatory

47 ripple, i.e., up to sol 510.

48 *Unless otherwise noted, names for features used in this paper are informal.

49 Background Discussion

50 MER Mission science objectives are focused on remote sensing and in-situ

51 observations along traverses to characterize current and past Martian environments and

52 the role of water in formation and alteration of the surface and associated crustal

53 materials [Squyres et al., 2003]. These objectives are aligned with the overarching NASA

54 Mars Exploration Program themes of “follow the water” and searching for evidence of

55 past or present habitable zones and life. For reference, on the other side of the planet the

56 Spirit rover has been exploring the Inner Basin, Columbia Hills, Gusev Crater, and has

57 acquired data that indicate the presence of hydrated sulfate, opaline, and carbonate-

58 bearing mineral deposits of likely fumarolic or hydrothermal origins [Arvidson et al.,

59 2008, 2010; Squyres et al., 2008; Morris et al., 2010]. Opportunity landed on the

60 Meridiani plains, selected primarily because the Mars Global Surveyor Thermal Emission

61 Spectrometer (TES) data indicated a high abundance of hematite, a mineral typically

62 formed in an aqueous environment [Christensen et al. 2001]. Data collected by

63 Opportunity within Eagle and Endurance craters conclusively showed that the hematite

64 signature is carried by hematitic concretions weathered from sulfate-rich bedrock and

65 concentrated as a surface lag, partly worked into basaltic sand ripples that cover much of

66 the plains [Soderblom et al., 2004; Sullivan et al., 2005; Arvidson et al., 2006; Jerolmack

67 et al., 2006]. Further, the sulfate-rich sandstones that comprise the Burns formation and

68 that underlie the ripples were found to be largely ancient aeolian sandstone deposits, with

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69 local reworking within ephemeral lakes [Squyres et al., 2004; Grotzinger et al., 2005,

70 2006; Metz et al., 2009]. Post depositional aqueous processes have altered the deposits as

71 evidenced by the presence of hematitic concretions and fracture-filling deposits

72 [McLennan et al., 2005; Knoll et al., 2008]. Opportunity has continued to search for the

73 mud-rich rock facies that would help confirm the hypothesis that the sands formed from

74 precursor evaporates in a playa lake environment.

75 The Burns formation rocks examined by Opportunity are part of a regional-scale

76 deposit that covers several hundred thousand square kilometers and is best explained by

77 accumulation during one or more periods of rising ground water [e.g., Andrews-Hanna et

78 al., 2010] (Fig. 1). These deposits are draped unconformably onto dissected cratered

79 terrain and exhibit an impact crater size frequency distribution indicative of a preservation

80 age of Noachian or Early Hesperian [Arvidson et al., 2006]. Pre-existing craters are also

81 evident and show partial burial by the sedimentary deposits, including the ~20 km

82 diameter Endeavour crater toward which Opportunity is traversing (Fig. 1). Bopolu is a

83 ~19 km diameter crater located to the southwest of Opportunity (Fig. 1). This crater

84 clearly post-dates the deposition of the sulfate-rich sedimentary deposits, given that the

85 floor and rim of the crater, along with its ejecta deposits, exhibit basaltic signatures

86 [Christensen et al., 2001] and the ejecta deposits extend over the sedimentary deposits

87 (Fig. 1). Bopolu, and other rayed craters on Meridiani Planum, lack hematite signatures on

88 their ejecta deposits, implying that these craters formed after the hematite was

89 concentrated on the surface [Golombek et al., 2010]

90 Detailed measurements conducted by Opportunity in Eagle and Endurance craters

91 showed the utility of impact craters for assessing the stratigraphy of the layered

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92 sedimentary rocks within Merdiani Planum [e.g., Squyres et al., 2006]. This approach was

93 continued during the period of the mission covered by this paper, including measurements

94 of strata within Erebus and Victoria craters, together with remote sensing and in-situ

95 observations of smaller craters and ejecta deposits encountered during traverses.

96 Opportunity has also continued to characterize aeolian deposits, cobbles, and the

97 atmosphere. Key results for all of these measurements are presented in this paper, along

98 with brief summaries of instrument and vehicle status, and a chronicle of traverses and

99 measurements from sols 511 to 2300.

100 Mission Overview

101 Rover and Payload Status: From sol 1 to sol 2300 Opportunity traversed 21,760

102 m and from sol 511 to sol 2300 16,389 m were covered, based on tracking wheel turns

103 (Fig. 2). For reference, Table 1 provides a summary of the Athena science payload, with

104 selected comments about status. Opportunity and its Athena payload were not designed

105 and built to travel over thousands of meters and operate over six and one half years.

106 Even so, the vehicle and payload have continued to operate well.

107 Opportunity’s right front steering actuator failed on sol 433, leaving the wheel

108 rotated inward by an ~8 degree angle. On sol 654 the Instrument Deployment Device

109 (IDD) experienced an un-stow anomaly because of a failing shoulder joint actuator. This

110 joint was declared “failed” on sol 1542 and since then the IDD has been left deployed

111 forward, carried in a “fishing stow” position while driving. IDD deployments have still

112 been possible, but within a more limited work volume as compared to earlier

113 measurements. Wheel currents for the right front wheel have occasionally spiked during

114 drives, perhaps because of uneven distribution of lubricant. The solution has been to

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115 rotate the affected wheel backwards and forwards to even out the lubricant and to “rest”

116 the wheel when currents spiked to particularly high values. The vehicle has primarily

117 been driven backwards during the mission period covered by this paper, in part to

118 minimize wheel actuator current spikes, and because this mode was found to permit

119 Opportunity to cross ripples with minimal mobility difficulties.

120 Opportunity has survived four Martian summers, with their associated dust storms

121 and periods of high atmospheric opacity (Fig. 3). Solar array energy has varied widely

122 from low values during the winter to high values during the summer, with strong

123 modulations based on the amount of dust in the atmosphere and on the solar panels. Dust

124 accumulation on the panels was predicted to end rover life much earlier, but winds have

125 removed dust on sols 520, 1150, 1305, 1520 (minor), 1620, 1846 (minor), 1990 (minor),

126 and 2300, providing instantaneous increases in available energy. Unlike Spirit, which is

127 located at -14.57° latitude, Opportunity’s near equatorial location (-1.95° latitude) has

128 provided enough sunlight to allow the vehicle to continue operations throughout the

129 winter seasons, although at a reduced pace relative to summer operations.

130 Dust coatings on the Pancam optical surfaces have made radiometric calibration

131 of images a continuing and involved process, particularly because the Pancam calibration

132 target on the rover deck has also accumulated dust. Dust has accumulated on the Navcam

133 and Hazcam exterior optical surfaces, but has not compromised the use of these cameras

134 for either scientific purposes or operations, including driving and IDD deployment

135 planning. During calendar year 2007 (~sol 1240, Fig. 3) a global dust storm deposited

136 dust on the Microscopic Imager (MI) exterior optics, both inside and outside the

137 protective dust cover. The dust cover seal is not airtight as it was designed to allow gas

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138 to escape during launch. Consequently, useful MI images can no longer be acquired with

139 the dust cover closed, and images taken with the dust cover open are visibly affected by

140 dust contamination. This contamination has reduced the signal/noise in Opportunity MI

141 images, but has not affected the ability to retrieve useful textural information from the

142 data. Unfortunately, dust accumulation on the Mini-TES exterior mirror compromised the

143 ability to retrieve quantitative information about mineralogy from data acquired after ~sol

144 1217. The instrument ceased responding to commands from the rover on sol 2257.

145 The Alpha Particle X-Ray Spectrometer (APXS) has continued to operate

146 nominally, acquiring compositional information for soils and rocks and making

147 measurements of atmospheric argon. The Mössbauer Spectrometer (MB) has also

148 continued to acquire data for soils and rocks, although significant decay of the cobalt-57

149 radioactive source (271.79 day half life) eventually required measurements extending

150 over several sols to achieve appropriately high spectral signal to noise values. The Rock

151 Abrasion Tool (RAT) has ground into 38 rocks over the course of the mission. During the

152 period covered by this paper 18 rocks were brushed and 15 were ground. By sol 2300 the

153 grinding bit pads were worn to ~20 to 30% of their original thicknesses and the brush was

154 slightly bent, no longer sweeping out a complete circle. All three RAT encoder motors

155 have stopped operating, leading to step-by-step manual approaches for commanding the

156 RAT to avoid a brush or grind failure or damage to the instrument.

157 Overview of Mission Activities: Table 2 provides a sol-by-sol description of

158 Opportunity’s activities. Fig. 3 shows a timeline of major activities with available solar

159 panel energy and atmospheric opacity on a sol-by-sol basis. Traverses have been mainly

160 from north to south, with stops in or near craters to examine rock strata and other “jogs”

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161 to examine important science targets or avoid large ripples (informally termed

162 “purgatoids” after the Purgatory ripple, where Opportunity was embedded between sols

163 446 and 484) (Fig. 2). By ~sol 2250, after bypassing several fields of purgatoids,

164 Opportunity was able to start traversing southeast, directly toward the rim of Noachian-

165 aged Endeavour crater, with the intent of exploring the ancient rocks exposed on the

166 crater’s rim.

167 The initial primary science target for Opportunity, after leaving Purgatory, was

168 Erebus, a ~220 m wide, degraded impact crater with ripples surrounding the crater and

169 occupying most of the crater floor (Fig. 2). Extensive remote sensing and in-situ

170 measurements were made on the Olympia outcrop on the northwestern side of Erebus

171 crater. Detailed remote sensing data were also acquired for the Payson outcrops located

172 on the southwestern side of Erebus. The Jammerbugt ripple was another location in

173 which significant wheel sinkage and slippage were encountered. Opportunity backed out

174 of this ripple on sol 841, after six sols of extrication. Several rock and soil targets, along

175 with small craters, were then examined during traverses to Victoria crater. Opportunity

176 reached Victoria’s crater rim on sol 953.

177 The first part of the Victoria campaign focused on remote sensing of crater walls,

178 done by driving to promontories and acquiring Pancam and Navcam mosaics of adjacent

179 cliff faces, together with acquiring data for cobbles strewn onto the smooth annulus

180 surrounding the crater (Fig. 2). This phase focused on the northwestern quadrant of the

181 crater and extended from sols 953 to 1290. After determining that Duck Bay was a

182 reasonable location to enter the crater and make measurements of Burns formation rock

183 targets as a function of depth, Opportunity entered Victoria on sol 1292 and stayed in the

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184 crater, acquiring detailed remote sensing and in-situ observations. Opportunity exited

185 Duck Bay on sol 1622. After soil measurements on the annulus surrounding Victoria, and

186 additional remote sensing of the crater walls, Opportunity on sol 1682 began traverses

187 toward Endeavour crater, located ~20 km to the southwest of Victoria.

188 During the post-Victoria traverses Opportunity encountered a number of impact

189 craters and a variety of cobbles and boulders, discussed in detail in a subsequent portion of

190 this paper. Key to successful traversing has been the avoidance of purgatoids, using Mars

191 Reconnaissance Orbiter HiRISE images [McEwen et al., 2007] and Odyssey THEMIS-

192 based thermal inertia maps [Christensen et al., 2003; Fergason et al., 2006], together with

193 extensive rover-based remote sensing observations, to drive along paths that minimized

194 traverses across large ripples [Parker et al., 2010]. This led to a southern to southwestern

195 path south from Victoria to avoid the purgatoid fields, and then turning to the southeast on

196 a more direct route to the rim of Endeavour (Fig. 2).

197 Modern Atmospheric Processes

198 In addition to addressing the primary mission themes of characterizing past

199 environmental conditions, and the role of water in formation and alteration of crustal

200 materials, Opportunity has continued to make periodic measurements that pertain to

201 current atmospheric characteristics and dynamics. Pancam has been used on a sol-by-sol

202 basis to determine atmospheric opacity at wavelengths of 440 and 880 nm. This activity

203 has supported mission operations tactically by providing estimates of available solar

204 irradiance on the panels. When combined with orbital observations, the Pancam

205 measurements have been critically important for tracking dust storms and the impact on

206 vehicle performance and safety. Regional dust storms have been observed during each

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207 summer season, with a planet-encircling event occurring during the early summer of the

208 third year of operations (~sols 1200-1300, see Fig. 3). This led to an available energy of

209 less than 200 watt-hours and placed Opportunity in a survival mode. Occasional dust

210 devils have been imaged by Opportunity and repeated coverage of the plains surrounding

211 Opportunity by the Mars Reconnaissance Orbiter’s Context Imager (CTX) [Malin et al.,

212 2007] showed a number of ephemeral dust devil tracks. Wind directions and magnitudes

213 were found by inspection of aeolian streaks, and mesoscale modeling of atmospheric

214 circulation models, to vary during the course of the Martian year [Sullivan et al., 2005;

215 Jerolmack et al., 2006; Chojnacki et al., 2010; Geissler et al., 2010].

216 Winter atmospheric measurements for science have focused on sky imaging to

217 detect the well-known winter aphelion water ice cloud “belt” [e.g., Clancy et al., 1996].

218 Fewer clouds were observed during the three periods near aphelion than would have been

219 predicted from Earth-based and orbital observations [i.e., Wolff et al., 1999]. The paucity

220 of clouds suggests that the meteorology of the Meridiani region may be more complex

221 (and thus more interesting) than previously understood.

222 When not in use to measure compositions of rocks and soils, and when rover

223 energy permitted, APXS has been used to monitor seasonal and inter-annual variations in

224 atmospheric argon contents (Fig. 4). The argon mixing ratio is a tracer for atmospheric

225 transport because it is a non-condensable gas under Martian conditions. On the other

226 hand, the carbon dioxide content of the atmosphere varies significantly as a function of

227 season because it condenses over the winter pole to form the seasonal ice cap. The

228 southern winter is longer and colder than the northern winter season because the southern

229 winter season occurs near aphelion. The southern pole is also topographically higher than

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230 the northern pole. Consequently, the southern winter carbon dioxide cap is more

231 extensive than the northern winter cap. These dynamics are evident in global pressure

232 variations recorded by the Viking Landers, with lowest surface pressures associated with

233 the southern winter [Tillman et al., 1993].

234 Sprague et al. [2007] reported global variations in argon mixing ratios using

235 Odyssey gamma ray spectrometer data, focusing on the six-fold argon enhancement

236 during the winter over the southern polar region (-75 to 90° latitude). Argon mixing ratios

237 were found to peak over the south pole at Ls=90 degrees and then undergo a rapid decline

238 to lowest values by the southern summer (Ls=270 degrees). Argon mixing ratios for an

239 adjacent latitude band (-60 to 75 degrees latitude) showed a similar pattern, but shifted to

240 a slightly later time. Argon was not found to concentrate above the north polar winter

241 cap. These patterns were interpreted as evidence for meridional transport of argon with

242 carbon dioxide as part of the global atmospheric circulation system, particularly

243 combined with relatively weak south pole to equator transient eddies that cause build-up

244 of argon over the winter cap [Nelli et al., 2007].

245 Opportunity-based argon atmospheric mixing ratios show minimum values at

246 Ls=90 degrees (beginning of the southern winter), during the period when argon shows

247 the highest concentration over the growing south polar seasonal cap (Fig. 4). The

248 Opportunity-based argon mixing ratios increase rapidly as the south polar concentrations

249 decrease. Peak Opportunity-based values are reached during late southern winter to early

250 spring seasons. Argon mixing ratios then start decreasing, reaching a broad low between

251 270 to 320 degrees Ls (northern winter season). The overall trends were simulated with

252 the NASA Ames global circulation model, which reproduced the broad patterns discussed

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253 above, including the sharp decrease and increase in Opportunity-based values associated

254 with the south polar winter cap formation and sublimation. The broad low associated with

255 formation and sublimation of the northern winter cap is also reproduced. The model fit to

256 the data shows temporal offsets and there are also inter-annual variations in Opportunity-

257 based argon mixing ratios. The differences between the model and the inter-annual

258 variations are currently study topics. It is clear that the Opportunity data provide

259 quantitative “ground truth” for use with Odyssey-based argon mixing ratios as tracers for

260 atmospheric circulation, along with “ground truth” validation of global circulation

261 models.

262 Aeolian Ripples and Mobility Issues

263 Nature and Origin: The plains surfaces traversed by Opportunity are largely

264 covered by aeolian ripples that have crests predominantly oriented in a north to south

265 direction. Hematitic concretions are concentrated on the ripple crests, whereas interiors

266 are dominated by a mix of basaltic sand, hematitic concretions, and dust [Christensen et

267 al., 2004; Soderblom et al. 2004; Sullivan et al., 2005; Arvidson et al., 2006; Jerolmack et

268 al., 2006]. Opportunity’s remote sensing measurements during traverses and stops for in-

269 situ measurements during the period covered by this paper show a change to larger

270 ripples and a greater areal exposure of outcrops, beginning ~280 m south of Purgatory

271 ripple (Fig 2). This change corresponds to a boundary between a relatively uniformly

272 dark, high thermal inertia surface covered by relatively small ripples to the north, to a

273 mix of bright and dark surfaces to the south (Fig. 2). The darker surfaces south of the

274 boundary, which are dominated by ripples, have low thermal inertias relative to the

275 surrounding brighter surfaces, which are dominated by bedrock exposures. South of

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276 Victoria fields of large ripples (i.e., purgatoids) identified using HiRISE images were

277 avoided during traverses by initially traversing to the southwest, then south, and finally

278 back to the southeast [Parker et al., 2010].

279 Detailed in-situ measurements of ripple surfaces and interiors collected throughout

280 the Opportunity mission provide key information on the nature and extent of these aeolian

281 features. For example, on sol 2297, at the end of a drive, Opportunity turned to maximize

282 UHF communication rates. The turn caused the right front wheel to cut into the crest of a

283 ripple, exposing the upper part of the interior (Fig. 5). MI data were acquired for the

284 excavated materials and an undisturbed surface target, Juneau, on the western flank of the

285 ripple. The Juneau images show a high areal concentration of hematitic concretions (Fig.

286 6), consistent with prior observations of ripple surfaces (Figs. 7). Specifically, application

287 of correspondence analysis [e.g., Arvidson et al., 2006; 2008; 2010] and comparison to MI

288 data show that the compositional trends associated with factor 1 loadings range from

289 basaltic sand samples (e.g., Auk target within Endurance crater), as one end member, to

290 almost complete areal coverage by hematitic concretions (e.g., Juneau), as the other end

291 member. In fact, the location of samples within this mixing line (i.e., factor 1 loading in

292 Fig. 7) is predicted with high fidelity based on the areal fraction of concretion coverage. A

293 minor, but important direction (factor 2 loading shown in Fig. 7) delineates targets with

294 enhanced sulfur and chlorine. MI data for these samples show the presence of fine-grained

295 materials (e.g., Les Houches, Fig. 6). These fine-grained targets are found adjacent to

296 Eagle (sol 60 data), Endurance (sol 123), and Victoria (sol 1647) craters and include dust

297 likely deposited in or near the craters in local aeolian traps.

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298 Ripples within the regions traversed by Opportunity have a dominant strike of

299 north-south, based on examination of HiRISE data and azimuths measured from Pancam

300 and Navcam data (Figs. 8-10). The Raleigh crater (Fig. 9) is part of the Resolution crater

301 cluster, a group of small impact craters spread over an area of ~ 120 m by 80 m, and is

302 located to the south of Victoria (Table 2). Rayleigh (and others within the cluster) must

303 have formed after the last major phase ripple migration ceased, since the crater cuts

304 across the ripples and exposes layers perpendicular to the ripple crest (Fig. 9) [Golombek

305 et al., 2010]. These exposures provide important information about the wind direction

306 that produced the ripple fields. The layers dip slightly toward the west. This pattern is

307 consistent with ripple formation by easterly winds in which sand was trapped on the

308 leeward faces and the ripple migrated over the deposits, producing layers that dip slightly

309 toward the leeward direction. The concentration of hematitic concretions on crests is due

310 to the fact that these relatively large grains travel in creep or traction mode and are left

311 behind as the sand saltates in the wind direction. Currently the dominant sediment-

312 moving winds vary in azimuth over time (e.g., Chojnacki et al., [2010]; Geissler et al.,

313 [2010]) and seem to have produced a set of subsidiary ripples and serrated the older,

314 larger ripple crests, depositing fine-grained materials within and on the large north-south

315 oriented ripples (e.g., Fig. 10). This trapping of fine-grained material is inferred to have

316 produced surfaces with slightly lower thermal inertias as compared to surrounding

317 bedrock or smaller ripples.

318 On a regional scale in Meridiani Planum low thermal inertia streaks are common

319 and extend to the west and northwest from craters and other topographic obstacles,

320 including the locations of the large ripples to the west and northwest of Endeavour crater

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321 (Fig. 11). These low temperature streaks have remained invariant during the 2002 to 2010

322 observation period of the Odyssey THEMIS IR observations and are interpreted to have

323 been produced by easterly to southeasterly winds. Global circulation models that simulate

324 the modern climate of Mars do not produce strong easterlies within the latitudes that

325 include Meridiani Planum (Fenton and Richardson, 2001; Haberle et al., 2003]. Indeed,

326 observations of fresh impact craters seen by Opportunity and HiRISE indicate that the

327 latest major phase of ripple migration occurred between ~50,000 to 200,000 years

328 [Golombek et al., 2010]. During earlier periods of time, when the spin axis of Mars was

329 at a higher orbital obliquity than the current value of 25 degrees, the solstice Hadley cell

330 circulation would have occupied a wider latitudinal belt and very likely produced strong

331 easterlies that generated the north-south oriented ripples observed by Opportunity. In

332 fact, modeling of obliquity changes shows that the obliquity can vary by 20° over a time-

333 scale of hundreds of thousands of years [e.g., Ward and Rudy, 1991], a timing consistent

334 with the last major ripple migration period as discussed above.

335 Mobility Issues: Crossing ripples with wavelengths larger than Opportunity’s

336 wheel base has occasionally proven to be problematic, leading to embedding at the

337 Purgatory and Jammerbugt ripples, and causing excessive wheel sinkage and slippage as

338 recently as sol 2220 (Table 2 and Figs. 12-13). These mobility difficulties occurred while

339 Opportunity attempted to drive up and over ripple flanks. To provide a quantitative

340 evaluation of these mobility difficulties a 200 element dynamical model of Opportunity

341 was constructed in software, including wheel-soil interactions with wheel sinkage and

342 slippage into deformable soils. This software was built on the framework developed for

343 modeling Spirit and its proposed extrication drives [Arvidson et al., 2010]. Normal and

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344 shear stresses between the wheels and soil were modeled using the classical Bekker-

345 Wong terramechanics expressions that describe relationships among normal pressure,

346 applied wheel torque, wheel slip, and wheel sinkage as a function of soil properties [e.g.,

347 Wong et al., 2003]:

n 348 σ= (kc/b + kφ)z (1)

349 τ= (c + σ tan (φ)) (1 – e-j/kx) (2)

350 where: σ is the normal stress and τ is the shear stress between the wheel and soil; kc/b is

351 the ratio of soil cohesion moduli to wheel width; kφ is the internal friction moduli, z is the

352 depth of wheel sinkage, n is a scaling exponent; c is the soil cohesion, φ is the soil angle

353 of internal friction, j is the slip value between the wheel and soil, and kx is the shear

354 deformation modulus in the longitudinal or drive direction. The value for j is determined

355 based on the magnitude of wheel sinkage into soil.

356 Increased wheel sinkage due to increased weight over a given wheel generally

357 leads to increased contact area between the wheel and soil and increased compaction

358 resistance, thereby increasing the amount of slippage, S, for a driven wheel as motor

359 torques are increased to compensate:

360 S = (1-V/Rω)*100 (3)

361 Where: V is the longitudinal velocity of the wheel, R is the wheel radius, and ω is the

362 wheel angular velocity. As slippage increases, additional sinkage generally occurs as soil

363 is moved in the direction of the spinning wheel. This further increases motion resistance

364 as the wheel comes in contact with additional soil during sinkage. At some point the

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365 maximum soil shear stress before failure is reached and slippage becomes effectively

366 100%, causing longitudinal motion to cease.

367 The sol 2220 drive ended when visual odometry [Maimone et al., 2007] showed

368 ~58% wheel slip, which was above the limit set for continuing the drive. This was a

369 fortuitous event for Opportunity since on-board use of the imaging systems to track slip

370 was done every ~20 m or so during a traverse. The high slip occurred when Opportunity

371 was driving backwards and scaling the western side of the ripple at an acute angle (~25°)

372 relative to the ripple crest azimuth, with a rover tilt magnitude of ~8° (Figs. 12-13). The

373 ~58% slippage values occurred when six wheels were on the ripple. Wheel sinkage

374 measured from Navcam data taken after extrication from the ripple was ~5 cm. The front

375 wheel (i.e., on the downslope side) tracks show evidence of slip sinkage, based on

376 disruption of the cleat imprints (Fig. 13).

377 To replicate the incipient embedding the Opportunity dynamic element model was

378 set to drive backwards on an 8° degree slope into nearly cohesionless soil (c~1 kPa) with

379 an angle of internal friction, φ=30°, following results from soil trenching experiments

380 conducted by Opportunity earlier in the mission [Sullivan et al., 2010]. Other parameters

381 in equations 1 and 2 were varied to match actual drive results, although detailed

382 sensitivity calculations showed that results were to first-order invariant to the chosen

383 values for kc. Thus, the modeling focused on varying numerical values of kφ, n, and kx.

384 The first two parameters control the amount of static sinkage whereas the third controls

385 the amount of slippage for a given sinkage magnitude. The models replicated observed

386 values of sinkage and slippage with n=1.1, kφ=75,000, and kx=65 mm. These values are

387 consistent with the presence of relatively soft soil into which the wheels for the 179

18

388 kilogram Opportunity rover would sink to a few centimeters on flat terrain. Also the

389 value for kx is toward the upper end of sandy soils for Earth and indicates that relatively

390 high slip values should occur with even modest sinkage and increased compaction

391 resistance. The lesson for mobility is to keep all six wheels from simultaneously being on

392 a ripple flank with the vehicle driving in an uphill direction. During the simulation it was

393 found that the middle and rear wheels bore most of the weight and thus underwent the

394 most sinkage, thereby significantly increasing compaction resistance. Slippage increased

395 as torque was increased to maintain constant wheel angular velocity, leading to slip

396 sinkage, and exceeding the 58% slippage limit for continuing the drive. Opportunity was

397 able to back out of the ripple with one drive and was then commanded to continue to

398 drive south along an inter-ripple zone until a smaller ripple system was encountered to

399 cross over toward the east.

400 Cobble and Boulder-Sized Rock Fragments

401 During the mission period covered by this paper Opportunity has characterized a

402 number of individual rock fragments with a variety of sizes. These rocks have been found

403 near craters, in isolated clusters covering small to moderate (10s to 100s m2) areas, and

404 sometimes as isolated pebbles, cobbles, or boulders separated by hundreds of meters. For

405 reference, Table 3 lists all rock fragments that were investigated in detail with IDD

406 instruments throughout the mission. Many additional cobble-sized and smaller rock

407 fragments have been characterized with Pancam, Navcam, and/or Hazcam observations

408 [e.g., Weitz et al., 2010]. These observations are not listed in Table 3.

409 Five basic types of rock fragments were found and characterized in detail during

410 Opportunity operations: 1. Local impact ejecta that consist of sulfate-rich sedimentary

19

411 material (e.g., Chocolate hills, Figs. 14-15); 2. Basaltic materials that are likely impact

412 ejecta fragments (e.g., Bounce Rock) from distant sources; 3. Rock fragments that are a

413 mix of sulfate and basaltic materials that are likely impact melt products (e.g., Arkansas);

414 4. Stony-iron meteorites (e.g., Barberton); and 5. Iron-nickel meteorites (e.g., Block

415 Island, Fig. 16).

416 Chocolate Hills is an ejecta fragment from Concepción crater, a ~10 m wide,

417 relatively fresh impact crater located on the plains to the south of Victoria (Figs. 2, 14-,

418 15). This rock is a finely layered, sulfate-rich material with hematitic concretions. The

419 rock is partially coated with a mix of basaltic sand and hematitic concretions cemented by

420 fine-grained hematite, based on analysis of MI, APXS, and MB data. The coating is

421 interpreted to be a fracture filling deposit similar in origin to the fins found in Victoria

422 crater and previous locations [Knoll et al., 2008]. Fins are indurated, fracture filling

423 materials that are now raised features due to differential aeolian erosion of the

424 surrounding softer sulfate-rich rocks. The presence of hematite implies that aqueous

425 processes have been operative at least episodically since formation of the sulfate-rich

426 sandstones that underlie Meridiani Planum.

427 Bounce Rock was encountered just outside of Eagle crater and is rich in pyroxene,

428 with a composition similar to the basaltic shergottite class of Martian meteorites [Zipfel et

429 al., 2010]. A possible source for this ejecta fragment is the ~20 km diameter Bopolu

430 crater, located ~75 km to the southwest of Eagle crater (Fig. 1). The boulder Marquette

431 Island was encountered during a traverse on the plains located to the south of Victoria

432 crater [Table 2 and Mittlefehldt et al., 2010]. The mineralogy and composition of

433 Marquette Island are similar to those of the Adirondack class of basalts examined by

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434 Spirit in Gusev crater. It probably originated as an ejecta fragment from an impact event

435 that penetrated the Noachian crust, either beneath the sulfate-rich sedimentary deposits,

436 or from the surrounding Noachian outcrops.

437 Arkansas is a relatively small, dark cobble that was found close to Erebus crater.

438 It is part of a group of cobbles found during traverses that were too small to brush or

439 grind. Undisturbed surfaces, where large enough to be imaged with the MI, sometimes

440 showed breccia-like textures. The composition and mineralogy of these cobbles indicate a

441 mix of materials, including sulfates. Most likely, the Arkansas group of cobbles

442 represents impact breccias strewn across the surface during local impact events and

443 concentrated on the plains by rapid aeolian erosion of bedrock relative to the more highly

444 indurated cobbles [Fleischer et al., 2010a].

445 The cobbles of the Barberton group [Barberton (on the southern rim of

446 Endurance), Santa Catarina (part of a strewn field on the rim of Victoria), Santorini, and

447 Kasos] are chemically and mineralogically similar and thus probably have a similar

448 origin [Schröder et al., 2010]. They are similar to mesosiderite meteorite silicate clasts,

449 but may represent a group of meteorites not sampled on Earth. The largest accumulation

450 of Barberton group cobbles, including Santa Catarina, is located near the rim of Victoria

451 crater. It is possible that they are paired fragments of the impactor that formed that crater

452 [Schröder et al., 2008; Ashley et al., 2009; Schröder et al., 2010].

453 Opportunity has discovered three large (>35 cm) Fe-Ni meteorites (Block Island,

454 Shelter Island, and Mackinac Island) south of Victoria crater [Fleischer et al., 2010b;

455 Ashley et al., 2010]. Each exhibits discontinuous surface coatings that appear purple in

456 Pancam false-color images (e.g., Fig. 16). For Heat Shield Rock, another Fe-Ni

21

457 meteorite located to the south of Endurance crater, most RAT-brushed surfaces exhibit

458 Pancam-derived spectra similar to laboratory spectra of the Canyon Diablo IAB meteorite

459 (Fig. 17). On the other hand, areas covered with purple coatings exhibit enhanced 535 nm

460 band depths, and more negative spectral slopes between 753 nm and 934 nm, as

461 compared to more typical natural or brushed surfaces on these meteorites (Fig. 17). A

462 nanophase iron oxide phase has, in fact, been identified in Mössbauer spectra associated

463 with the purple coatings [Fleischer et al., 2010b]. Additionally, a minor, magnetically

464 ordered iron oxide phase has been identified in spectra from Heat Shield Rock, inferring

465 a small amount of relatively well-crystallized and larger particles (i.e., not nano-particles)

466 [Fleischer et al., 2010b]. In addition, APXS data for the Fe-Ni meteorites show elevated

467 Br, Zn, and Mg values consistent with surface alteration.

468 Schröder et al., [2008] and Ashley et al., [2010] suggested that the coatings on the

469 Fe-Ni meteorites represent remnants of a partially wind-eroded coating that formed when

470 portions of the rock were buried, rather than a remnant fusion crust formed during

471 traverse through the Martian atmosphere. These Fe-Ni meteorites have also undergone

472 significant physical weathering (e.g., Mackinac Island has a cavernous interior) [Ashley et

473 al., 2010]. The length of time that these meteorites have been on or near the surface is

474 difficult to estimate. The size and mass of Heat Shield Rock and Block Island have been

475 used as evidence that they landed during a period when the atmosphere was denser and

476 slowed their descent [Beech and Coulson, 2010]. Otherwise they would have been

477 destroyed during the subsequent hypervelocity impact with the surface. Alternatively, the

478 landings would also have been possible with shallow entry angles under current

479 atmospheric conditions [Chappelow and Golombek, 2010]. In any case, the extent of

22

480 weathering of these Fe-Ni meteorites, combined with the presence of iron oxides in the

481 stony-iron meteorites examined by Opportunity, will continue to provide insight into

482 weathering processes on Mars.

483 Observations of fresh craters younger than the north-trending ripples (e.g., the

484 Resolution crater cluster and Concepción) show abundant dark pebbles scattered across

485 their surfaces. Given the apparent young ages of these craters, the straight-forward

486 explanation is that these dark pebbles are fragments of the impactors, suggesting that the

487 widespread dark pebbles and cobbles observed by Opportunity at Meridiani Planum are

488 lags of impactor-derived material (either meteoritic or secondary impactors from

489 elsewhere on Mars) [Golombek et al., 2010].

490 Bedrock and Environments of Deposition and Alteration

491 The sulfate-rich sandstones that comprise the Burns formation and examined by

492 Opportunity within Eagle and Endurance craters provide compelling evidence of

493 deposition by wind, with local subaqueous reworking within inter-dune ephemeral lakes

494 [e.g., Squyres et al., 2004; 2006; Grotzinger et al., 2005]. Sulfate cements and hematitic

495 concretions attest to multiple, but possibly short-lived episodes of percolation by acidic

496 ground waters [McLennan et al., 2005]. Recent calculations indicate that in-situ iron

497 oxidation could have provided sufficient acidity to explain the Burns formation

498 mineralogy [Hurowitz et al., 2010]. Inferred grain compositions indicate that the sands

499 were sourced in places where waters interacted with and weathered basaltic precursor

500 rocks [Squyres et al., 2004; Squyres and Knoll, 2005]. During the period covered by this

501 paper Opportunity explored outcrops on the plains and ventured into Erebus and Victoria

502 craters to continue stratigraphic measurements designed to understand in more detail the

23

503 origin and environments of deposition that produced the layered sulfate rocks that

504 underlie the Meridiani plains (Fig. 1). Particular emphasis was placed on the search for

505 evidence of a sulfate-rich mud facies that might have been the source of the sandstones

506 encountered by Opportunity. Finding those deposits would allow confirmation or

507 rejection of the hypothesis that the sands were sourced in an evaporitic lake environment.

508 The first set of very detailed measurements focused on the Olympia outcrops

509 exposed to the northwest side of Erebus crater, together with a vertical section, dubbed

510 Payson, on the southwestern wall of Erebus (Figs. 18-19). The ripple patterns in these

511 outcrops provide compelling evidence for water transport of sulfate-rich sands,

512 subsequently cemented to become sandstones [Grotzinger et al., 2006; Metz et al., 2009].

513 The Payson outcrop also showed disruption by water of laminated sandstones and the

514 presence of shrinkage cracks, all consistent with an ephemeral shallow water

515 environment. Compositional and mineralogical measurements acquired at the Olympia

516 outcrops are very similar to measurements acquired in Eagle and Endurance craters. No

517 in-situ measurements were acquired at the Payson outcrops. The Olympia area is also the

518 one place where it has proven possible to obtain in-situ analyses of fin-like fracture fill,

519 confirming that these features originated as clastic infillings of partings, later cemented to

520 provide differential resistance to erosion. The fill is chemically similar to bedrock

521 materials and not to modern soils. Taken together, the evidence suggests that these

522 features formed after the primary phases of deposition and diagenesis, but prior to

523 deposition of the modern soils (Knoll et al., 2008).

524 Victoria is the largest crater examined by Opportunity to date, ~750 m wide and

525 ~75 m deep. It was a primary target for exploration during the sols covered by this paper

24

526 because of the extensive Burns formation stratigraphic exposures on its walls (Figs. 2 and

527 20) [Squyres et al., 2009]. The approach to Victoria from the northwest allowed

528 traversing across the annulus surrounding Victoria, a planar region that was found to

529 consist of aeolian basaltic sands and hematitic concretions that partially cover the tops of

530 beveled ejecta blocks (Fig. 21). The ejecta deposit consists of relatively soft sulfate-rich

531 rocks evenly eroded by wind to form the planar annulus that surrounds the crater [Grant

532 et al., 2008]. Remote sensing of the crater wall from various promontories on the rim of

533 Victoria showed that blocky ejecta deposits dominate the upper few meters of wall rock

534 (Fig. 22). The ejecta blocks are layered, contain hematitic concretions, and have

535 coloration consistent with an origin as sulfate-rich bedrock. There is no evidence from

536 Victoria’s wall rocks or ejecta that the impact event penetrated into the underlying

537 Noachian crust.

538 Duck Bay was chosen for entry into Victoria for detailed measurements because of

539 the extensive Burns formation outcrops and the relatively easy ingress and exit paths

540 (Fig. 23). Beneath the ejecta deposit exposed at Duck Bay are four discrete layers that

541 were examined using both remote sensing and in-situ instrumentation [Squyres et al.,

542 2009]. Steno is the layer in contact with the ejecta and is underlain by a relatively bright

543 layer, Smith. Lyell and Gilbert are the next two layers examined during the Duck Bay

544 campaign. Steno consists of a fine to medium-grained sandstone with well-defined

545 laminae. Cross-bedding is evident, as are hematitic concretions. Steno is separated from

546 Smith by an unconformity. Smith is a relatively bright sandstone and exhibits fine-scale

547 laminations. Lyell is transitional with Smith and exhibits tabular, prismatic vugs, cross-

548 bedding, and an abundance of hematitic concretions. Gilbert was only measured in one

25

549 location and the contact with Lyell is gradational. Lyell and Smith are also sandstones.

550 Pancam observations show that the Smith unit has an abrupt spectral down-turn at 1000

551 nm, consistent with the presence of the molecular water vibrational mode 2v1 + v3 and

552 3vOH for OH-bearing minerals (Fig. 23) [see: Rice et al., 2010]. No evidence was found

553 in any of the layers for the mud facies that might have been the source for the sulfate-rich

554 sandstones. In fact, the rocks examined in Victoria, both using remote sensing from

555 capes, and detailed measurements in Duck Bay, are best interpreted as sulfate-rich

556 aeolian sands altered and cemented by ground water infiltration [Squyres et al., 2009].

557 In-situ data were acquired for undisturbed, brushed, and ratted rock targets within

558 each of the four stratigraphic layers in Duck Bay. Correspondence analysis shows the

559 importance of removing aeolian sand and dust covers and any coatings from these rocks

560 to understand their intrinsic characteristics (Fig. 24). In particular, the first factor in

561 APXS data, accounting for 92% of the variance of the data set, shows a trend from

562 basaltic to more sulfate-rich materials for natural, brushed, as opposed to ratted targets.

563 Ratted targets have the highest sulfur content and least contamination by coatings or

564 basaltic sands. The second factor, accounting for 4% of the variance, shows that the

565 ratted rock targets can be discriminated from one another on the basis of chlorine content,

566 with Gilbert showing the highest value, and Steno the lowest. A trend of increasing

567 chlorine content with increasing depth is also evident in a scatter plot of chlorine to silica

568 content as a function of depth (Fig. 25). On the other hand, the sulfur and magnesium

569 contents, relative to silica, both decrease as a function of depth beneath the surface (Fig.

570 26). These compositional patterns correlate well with the hydration index computed from

571 the depth of the 1000 nm band evident in the Smith unit (Fig. 24). Further, this bright,

26

572 upper unit appears to continue around the entire crater and can be fit with a horizontal

573 plane [Hayes et al., 2010].

574 The rocks examined in Duck Bay, although still part of the Burns formation, are

575 separated laterally and topographically from the Karatepe section outcrops examined in

576 Endurance crater. Even so, the Karatepe section also shows a bright upper layer (above

577 the Whatanga contact) that is depleted in chlorine relative to silica and enhanced in

578 magnesium and sulfur relative to silica as compared to rocks exposed at greater depths

579 (Figs. 25-26) [also see Squyres et al., 2009]. In addition, the VNIR multispectral

580 character of both sets of strata is similar [Farrand et al., 2007]. Hayes et al., [2010],

581 examining orbital data, found that bright layers are evident in a number of other craters

582 that formed in the Burns formation. Overall, the evidence is interpreted to reflect

583 regional-scale differential vertical mobility of soluble sulfate and chloride salts during

584 near surface aqueous-mediated diagenesis [Clark et al., 2005; also see Amundson et al.,

585 2008]. The observation that Victoria ejecta deposits include fragments of the Smith unit

586 implies that the aqueous alteration event predates formation of Victoria [Edgar et al.,

587 2010].

588 The Rim of Endeavour Crater and Adjacent Layered Sedimentary Rocks

589 Opportunity has thus far been exploring sedimentary rocks and soils that

590 unconformably overlie the Noachian crust (Fig. 1). Endeavour crater predates the

591 sedimentary deposits and the crater rim exposes materials of Noachian age (Figs. 1, 27-

592 28). This is clear from geologic mapping and also initial spectral analysis of CRISM

593 hyperspectral data [Murchie et al., 2007] covering the rim and surrounding areas.

594 Specifically, Wray et al. [2009] showed from analysis of CRISM spectra covering 0.4 to

27

595 2.5 µm in wavelength that portions of the rim expose iron and magnesium-rich smectite

596 clay minerals. In addition, these authors showed that the sedimentary rocks adjacent to

597 the rim have spectra that are indicative of hydrated sulfates.

598 The long term objectives for the Opportunity extended mission are to drive to the

599 hydrated sulfate deposits and Noachian-aged rim materials of Endeavour. By sol 2239 the

600 rover was within ~11 km of the rim (Fig. 27). Pancam color and super-resolution imaging

601 (Fig. 28), combined with periodic collection of imaging data from the HiRISE, CTX, and

602 CRISM instruments, are helping to define traverses to locations where the hydrated

603 sulfate sedimentary rocks and altered rim materials are best exposed and accessible to

604 Opportunity. Outcrops of the Burns formation that have been characterized thus far by

605 Opportunity exhibit OMEGA-based and CRISM-based reflectance spectra that indicate

606 the spectral dominance of anhydrous phases [e.g., Arvidson et al., 2006]. This result is

607 consistent with the dominance of nanophase iron oxide coatings on rock surfaces [e.g.,

608 Knoll et al., 2008], and with the observation that the 6 µm bending vibration for water is

609 not evident in Mini-TES for undisturbed rock surfaces [Glotch et al., 2006]. On the other

610 hand, Mini-TES deconvolution of ratted Burns formation material, including constraints

611 from MB and APXS measurements, indicate the presence of hydrated Mg and Ca-sulfate

612 minerals [Glotch et al., 2006]. The surface exposures of hydrated sulfates close to the rim

613 of Endeavour are likely layers that lie stratigraphically beneath the Burns formation rocks

614 examined by Opportunity. Characterizing the composition, mineralogy, and texture of

615 these older sedimentary rocks will provide new information on paleoenvironmental

616 conditions and perhaps even provide the evidence for the source rocks for the sulfate-rich

617 aeolian sandstones that dominate the Burns formation. In addition, Opportunity’s

28

618 characterization of Endeavour’s rim rocks, including clay minerals, will allow even older

619 environmental conditions to be reconstructed.

620 Conclusions

621 Opportunity has been traversing across the plains of Meridiani since January

622 2004, far exceeding the expected lifetimes and traverse distances of the rover, and using

623 its Athena scientific payload for many more measurements than originally planned.

624 Opportunity has operated over three Martian years and acquired important information on

625 modern atmospheric dynamics, including atmospheric opacity, clouds, and use of

626 atmospheric argon as a tracer for circulation dynamics. The aeolian ripples traversed by

627 Opportunity were generated by easterly winds in an ancient environment, probably within

628 hundreds of thousands of years, when the spin axis obliquity was higher and Hadley cell

629 circulation enhanced. Cobbles and boulders examined by Opportunity include local and

630 regional-scale ejecta blocks, together with both stony iron and iron-nickel meteorites. The

631 meteorites have undergone both physical and chemical weathering and are likely a lag of

632 impactor-derived materials. Opportunity has made measurements within Eagle,

633 Endurance, Erebus, and Victoria craters, together with outcrop exposures on the plains

634 that were focused on characterizing the formation and modification of the Burns

635 formation sulfate-rich sandstones. Results continue to show compelling evidence of sand

636 deposition by wind, with local reworking within ephemeral lakes. Extensive lacustrine

637 evaporitic facies have not yet been found, although particular emphasis has been placed

638 on finding these putative materials. Accessing the hydrated sulfate rocks near the

639 Endeavour crater rim and the clay minerals on the rim proper will open a new chapter for

29

640 Opportunity and allow characterization of materials not yet encountered during the

641 mission.

642 Acknowledgements

643 We thank the capable team of engineers and scientists at the Jet Propulsion Laboratory

644 and elsewhere who made the Opportunity mission possible. We also thank support from

645 NASA for the MER science team to allow both collection and analysis of data from

646 Opportunity. Alejandro Soto and Mark Richardson provided valuable comments on an

647 earlier draft of this paper and we thank them for their efforts.

648 References

649 650 Amundson, R., S. Ewing, W. Dietrich, B. Sutter, J. Owen, O. Chadwick, K. Nishiizumi, 651 M. Walvoord, and C. McKay (2008), On the in situ aqueous alteration of soils on 652 Mars, Geochim. Cosmochim. Acta, 72, 3845-3864. 653 654 Andrews-Hanna, J. C., M. T. Zuber, R. E. Arvidson, and S. J. Wiseman (2010), Early 655 Mars Hydrology: Meridiani playa deposits and the sedimentary record of Arabia 656 Terra, J. Geophys. Res., 115, E06002, doi:10.1029/2009JE003485. 657 658 Arvidson, R. E., F. Poulet, R. Morris, J. -P. Bibring, J. Bell III, S. Squyres, P. 659 Christensen, G. Bellucci, B. Gondet, B. Ehlmann, W. Farrand, R. Fergason, M. 660 Golombek, J. Griffes, J. Grotzinger, E. Guinness, K. Herkenhoff, J. Johnson, G. 661 Klingelhofer, Y. Langevin, D. Ming, K. Seelos, R. Sullivan, J. Ward, S. Wiseman, 662 and M. Wolff (2006), Nature and Origin of the Hematite-Bearing Plains of Terra 663 Meridiani Based on Analysis of Orbital and Mars Exploration Rover Data Sets, J. 664 Geophys. Res., 111, E12S08, doi:10.1029/2006JE002728. 665 666 Arvidson, R. E., S. Ruff, R. V. Morris, D. W. Ming, L. Crumpler, A. Yen, S. W. Squyres, 667 R. J. Sullivan, J. F. Bell III, N. A. Cabrol, B. C. Clark, W. Farrand, R. Gellert, R. 668 Greenberger, J. A. Grant, E. A. Guinness, K. E. Herkenhoff1, J. Hurowitz , J. R. 669 Johnson, G. Klingelhöfer, K. Lewis, R. Li, T. McCoy, J. Moersch, H.Y. McSween, S. 670 Murchie, M. Schmidt, C. Schröder, A. Wang, S. Wiseman, M. B. Madsen, W. Goetz, 671 and S. McLennan (2008), Spirit Mars Rover Mission to the Columbia Hills, Gusev 672 Crater: Mission Overview and Selected Results from the Cumberland Ridge to Home 673 Plate, J. Geophys. Res., 113, E12S33, doi:10.1029/2008JE003183. 674

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Figure Captions

996 Figure 1 – Geologic map for the southern portion of the Meridiani Planum layered

997 sedimentary rocks (ph, hematite-bearing plains) and the Noachian-aged dissected cratered

998 terrain (dct), with cross section. Miyamoto is a partially buried impact basin that predates

999 deposition of the layered sedimentary sequence. Endeavour and Iazu are Noachian craters

1000 partially buried by the layered materials, as is the channel system mapped as “ch”. The ph

1001 unit unconformably overlies the dct and ch units and is interpreted from impact crater

1002 densities to have been emplaced in late Noachian to early Hesperian times [Arvidson et

1003 al., 2006]. The crater Bopolu post-dates the emplacement of the layered materials and

1004 excavated beneath the deposits to expose dct materials within the crater and on the ejecta

1005 deposit. Opportunity’s ~22 km (as of 7/27/10) of traverses are overlain as a black line. A

1006 THEMIS daytime IR mosaic was used as a map base. White box delineates area shown in

1007 Fig. 11.

1008 Figure 2 – Portion of a CTX image P15_006847_1770_XN_03S005W_080111 covering

1009 Opportunity’s traverses and immediate surroundings. Eagle, Endurance, Erebus, Victoria,

1010 Raleigh, and Concepción craters are shown, along with the traverse direction to

1011 Endeavour, located about 11 km to the southeast of the sol 2300 location. Block Island is

1012 an iron meteorite discovered south of Victoria. Key sols are shown, including the location

1013 of the Purgatory ripple, where the previous overview paper [Squyres et al., 2006] ended

1014 its summary of operations and science highlights. Bright areas correspond to regions

1015 with extensive outcrop whereas darker areas are widely covered by aeolian ripples.

39

1016 Figure 3 – Time series available rover energy, atmospheric opacity, and major events for

1017 Opportunity from sol 511 to sol 2300. Opacity at 880 nm is shown multiplied by a factor

1018 of two hundred.

1019 Figure 4 – Scaled volume mixing ratios of argon to carbon dioxide are shown for three

1020 years of Opportunity APXS observations of the atmosphere, together with mixing ratios

1021 derived from the NASA Ames general circulation model. Both data sets have been scaled

1022 by subtracting means and dividing by standard deviations. The southern winter solstice

1023 occurs at Ls=90° whereas the northern winter solstice occurs at Ls=270°. See text for

1024 explanation of trends.

1025 Figure 5 – Front Hazcam image looking to the north showing a drive and turn in place

1026 across the crest of a ripple. Outcrop is shown as bright polygonal regions on either side of

1027 the ripple. Juneau is the location of an IDD target on the western flank of the ripple. MI

1028 data for Juneau show that it is covered with a dense array of hematitic concretions (Fig.

1029 6). Front Hazcam frame 1F331928037RSLAKVTP1214L0MZ acquired on sol 2295.

1030 Figure 6 – Series of MI images, each 3 cm across, of soils encountered during

1031 Opportunity’s traverses. Juneau is a ripple surface dominated by hematitic concretions.

1032 Auk sand was encountered in Endurance crater whereas the fine-grained dust target, Les

1033 Houches, was found on the perimeter of Eagle crater. These targets form compositional

1034 end-members in the APXS data, as shown in Fig. 7.

1035 Figure 7 – Correspondence analysis plot showing all undisturbed soil targets for which

1036 APXS data were acquired. Numbers in parentheses correspond to the ratio of ferric to

1037 total iron for the targets based on MB observations. The primary trend is from basaltic

1038 sands on the right side of the diagram to high concentrations of hematitic concretions on

40

1039 the left. Targets with enrichments in dusty material map separately from the dominant

1040 sand to concretion “mixing line”. Iron oxidation states are consistent with the inferred

1041 mineralogy, with higher values for targets with a higher abundance of hematitic

1042 concretions.

1043 Figure 8 – HiRISE view of ripples around Rayleigh crater, along with Opportunity’s

1044 traverses and sols shown for selected positions. Note the bright outcrop and extensive

1045 coverage by north-south trending aeolian ripples. Portion of HiRISE frame

1046 ESP_016644_1780_red.jp2.

1047 Figure 9 – Navcam view looking to the south into the ~2 m wide Rayleigh crater. Note

1048 the eastern ripple slope exposes light and dark bands that can be extended to the third

1049 dimension by noting the cross stratification on the northern Raleigh crater wall.

1050 Stratification is consistent with formation of ripples by easterly to southeasterly winds, as

1051 discussed in the text. Image acquired on Sol 1852 with Discovery crater can be seen in

1052 the background. Navcam frame 1N292594992RSD99NGP1921L0MZ.

1053 Figure 10 – Pancam false color image mosaic looking north and showing the bright red

1054 western sides of ripples. Pancam bands L2 (753 nm), L5 (535 nm), and L7 (432 nm) are

1055 shown as red, green, and blue. Data acquired on sol 1858, after a major dust storm.

1056 Figure 11 – Color-coded predawn THEMIS IR scaled temperature values and

1057 Opportunity’s traverses overlain onto THEMIS daytime IR mosaic. Arrows show low

1058 temperature streaks extending eastward from craters. Note also the low temperature zone

1059 to the west of Endeavour, including regions traversed by Opportunity. Red colors

1060 correspond to terrains with thermal inertias between ~155 and 180 J m-2 K-1 s-1/2 and blue

1061 to regions with thermal inertias between ~140 and 145 J m-2 K-1 s-1/2. Box shows region

41

1062 covered in Fig. 2. Lower thermal inertia areas are dominated by fields of relatively large

1063 ripples that have trapped fine-grained aeolian deposits. Bedrock has slightly higher

1064 thermal inertias than ripples.

1065 Figure 12 – HiRISE view of sol 2220 high slippage and sinkage location on the western

1066 side of a ripple. Locations A and B are shown on the Navcam view in Fig. 13. Portion of

1067 HiRISE frame ESP_016644_1780_red.jp2.

1068 Figure 13 – Navcam image acquired on sol 2226 of the sol 2220 high slippage and

1069 sinkage location on the western side of a ripple. The shallow angle of attack relative to

1070 the ripple crest put all six wheels on the relatively soft soil. During its climb up the ripple

1071 slip equaled 58% and the drive was halted by on-board Visodom software. Navcam frame

1072 1N325805274RSDAG12P19170L0MZ.

1073 Figure 14 – Pancam false color view of Concepción crater acquired on sol 2140,

1074 including the Chocolate Hills and Loboc River boulders, when Opportunity was ~5 m

1075 from the northern rim. Ejecta from this impact event are superimposed on the

1076 surrounding ripples. The crater is partly filled with aeolian basaltic sand. Detailed IDD

1077 work was done on Chocolate Hills. Pancam bands L2 (753 nm), L5 (535 nm), and L7

1078 (432 nm) are shown as red, green, and blue colors. .

1079 Figure 15 – Pancam color view of the Chocolate Hills boulder showing fine-scale

1080 layering and a coating of dark material. MI views with Pancam color overlays (labeled

1081 "Super Res") show the presence of hematitic concretions. Pancam image acquired on sol

1082 2147 using bands L2 (753 nm), L5 (535 nm), and L7 (432 nm) as red, green, and blue

1083 colors, respectively

42

1084 Figure 16 – a. Pancam enhanced false-color image (RGB as 753 nm, 535 nm, 432 nm) of

1085 the Fe-Ni meteorite Block Island (~65 cm wide). Box outlines areas shown in part b. b.

1086 MI mosaic of upper portion of Block Island (~7.5 cm across; merged with Pancam false-

1087 color image) showing purple-hued coatings.

1088 Figure 17 – Pancam spectra (R*, relative reflectance normalized to cosine (incidence

1089 angle)) of Fe-Ni meteorites for (left) “typical” surfaces and (right) purple surfaces,

1090 compared to laboratory spectrum of Canyon Diablo convolved to Pancam band-passes

1091 (offset by -0.1 for clarity). Spectra for Heat Shield Rock from Schröder et al. [2008]

1092 show surfaces pristine and brushed using the RAT. Pancam sequence identification

1093 numbers shown in legends. Error bars represent standard deviations of pixels selected for

1094 regions of interest in Pancam images. Canyon Diablo laboratory spectrum is RELAB

1095 MI-CMP-008, spectrum 001.

1096 Figure 18 – HiRISE view of the highly degraded Erebus crater, with Opportunity

1097 traverses shown, along with representative sols and key targets. Opportunity conducted

1098 extensive remote sensing and IDD measurements at the Olympia outcrops (bright

1099 regions). For the Payson outcrop, which constitutes the southwestern wall of Erebus

1100 crater, systematic remote sensing was conducted while Opportunity traversed south

1101 toward Victoria crater. Note the extensive north-south trending ripples covering the crater

1102 and surrounding plains. Portion of HiRISE frame ESP_016644_1780_red.jp2.

1103 Figure 19a – Portion of a Navcam mosaic looking toward the west of a portion of the

1104 Payson outcrop acquired on sol 747. The outcrop height is ~1.6 m and relatively dark

1105 ripples can be seen in the plains beyond Payson. Note the outcrop cross bedding dipping

1106 toward the south. Box shows location of Pancam frame shown in Fig. 19b.

43

1107 Figure 19b – Pancam view of a portion of the Payson outcrop showing approximately a

1108 dozen fine-scale, cross-bedded layers. The ripple patterns are indicative of shallow

1109 subaqueous transport, similar in interpretation to the ripple patterns in the sandstones

1110 observed to the north in the Olympia outcrop on the northwestern side of Erebus. Height

1111 covered in the image is ~1.4 m. Pancam frame 1P194853277RSD646BP2547L7MZ

1112 acquired on sol 751.

1113 Figure 20 – HiRISE view of Victoria crater showing Opportunity’s traverses, including

1114 drives into and out of Duck Bay for detailed IDD work on outcrops. The outcrop

1115 examined by Opportunity within Bottomless Bay is shown in a Pancam color view in Fig.

1116 22a. Traverses around a portion of Victoria’s rim were conducted to map outcrops and to

1117 find a bay into which ingress and exit could be made with relatively low risk of

1118 embedding. Portion of HiRISE frame ESP_016644_1780_red.jp2.

1119 Figure 21 – Pancam false color view of the Victoria ejecta deposit apron showing the

1120 tops of boulders that have been leveled by aeolian erosion and partially covered by soil

1121 with a relatively high concentration of hematitc concretions. The tear-drop shaped

1122 boulder on the top half of the frame is ~0.9 m long. The target area is Malua and the data

1123 were acquired on sol 1029. Pancam bands L2 (753 nm), L5 (535 nm), and L6 (482 nm)

1124 are shown as red, green, and blue colors.

1125 Figure 22a – Pancam false color view of the outcrop on the southwestern side of

1126 Bottomless bay and a portion of the overlying ejecta deposit and annulus. Box shows

1127 region for which a geologic sketch map is shown in Fig 22b. Data acquired on sol 1037.

1128 Pancam bands 2 (0.753 µm), 5 (0.535 µm), and 7 (0.432 µm) are shown as red, green,

1129 and blue colors.

44

1130 Figure 22b – Geologic sketch map showing in place bedrock, fractured bedrock, and

1131 poorly sorted ejecta blocks superimposed on the fracture bedrock surface. The ejecta has

1132 been leveled by aeolian erosion to form the annulus surrounding Victoria. Note rover

1133 tracks.

1134 Figure 23 – Portion of a Pancam false color mosaic covering the stratigraphic section

1135 examined by Opportunity during its traverses within Duck Bay, Victoria crater. The

1136 mosaic data were acquired between sols 970 to 991 as part of the Cape Verde panorama.

1137 Steno is the top-most in-place outcrop beneath the ejecta deposit. The brighter layer,

1138 Smith, can be found in many locations around the perimeter of the crater. Pancam 13F

1139 spectra for Smith, Lyell, and Gilbert are shown in the lower right and discussed in detail

1140 in the text. A hydration index based in the depth of the 1.0 µm band is shown on the

1141 lower left and indicates that the Smith unit is hydrated. The hydration index covers the

1142 left portion of the Pancam false color mosaic and is centered vertically on the Smith unit.

1143 Pancam bands 2 (753 nm), 5 (535 nm), and 7 (432 nm) are shown as red, green, and blue

1144 colors.

1145 Figure 24 – Correspondence analysis plot for APXS data acquired for rock outcrops in

1146 Duck Bay, Victoria crater. The highest fractional variance is controlled by changes in

1147 chemistry from natural surfaces, contaminated by aeolian basaltic soils and coatings, to

1148 ratted surfaces that better represent the sulfate-rich outcrop chemistry. Brushed targets are

1149 denoted by “_b” after names. Targets in italics have been ratted (“_r”) and numbers in

1150 parentheses correspond to ferric iron to total iron values from MB observations. The

1151 direction of second highest fractional variance separates ratted targets based on chlorine,

45

1152 sulfur, and magnesium contents, as shown by scatter plots in Figs. 25 and 26. Box in

1153 upper right is a schematic stratigraphic section. .

1154 Figure 25 – APXS-based chlorine/SiO2 values are shown as a function of depth beneath

1155 the ejecta to bedrock contact for ratted targets in Victoria and Endurance craters. The

1156 presence of the bright upper layer in both craters and the increase in Cl/SiO2 with

1157 increasing depth indicates a regional-scale aqueous process that concentrated relatively

1158 soluble Cl in lower stratigraphic horizons. The bright layer corresponds to the Smith unit

1159 in Victoria and to rock targets above the Whatanga contact for the Endurance Karatepe

1160 section. Endurance targets Virginia, Kentucky, Ontario, and Tennessee are above the

1161 Whatanga contact.

1162 Figure 26a and b show decreasing values of MgO and SO3 relative to SiO2 with depth

1163 beneath the ejecta to bedrock contact for both Endurance and Victoria craters, implying a

1164 regional scale aqueous alteration process that led to an enrichment of relatively insoluble

1165 magnesium sulfates in the bedrock upper layers.

1166 Figure 27 – CTX mosaic with Opportunity traverses shown and locations on the rim of

1167 Endeavour labeled. The white lines extending from the sol 2239 position cover the field

1168 of view of the Pancam super-resolution images of the rim of Endeavour shown in Fig. 28.

1169 Mosaic generated from CTX frames P13_006135_1789_XN_01S005W_071117,

1170 P15_006847_1770_XN_03S005W_080111, and

1171 P17_007849_1793_XN_00S005W_080330.

1172 Figure 28 – Pancam super-resolution view of a portion of Endeavour’s rim and Iazu

1173 ejecta acquired from ~13 km distance. Cape Tribulation has exposures of Fe-Mg smectite

1174 clay minerals based on analyses of CRISM data [Wray et al. 2009]. Analysis of CRISM

46

1175 data also indicate the presence of layered sedimentary rocks with hydrated sulfate

1176 signatures adjacent to the rim [Wray et al. 2009]. This image was generated from a series

1177 of eight Pancam frames acquired on sol 2239.

1178

47

1179 Table 1 – Opportunity’s Payload Elements. Magnets were also included on the spacecraft 1180 but not described in this table. Instrument Key Parameters Mast-Mounted Science Instruments Pancam: Panoramic Multi-spectral imager (~400 to 1000 nm) with stereoscopic capability; 0.28 Camera mrad IFOV; 16.8 deg by 16.8 deg FOV. Stereo baseline separation of 30 cm. External calibration target on rover deck. Mini-TES: Thermal Emission spectra (5 to 29 µm, 10 cm-1 resolution) with 8 or 20 mrad FOV. Emission Spectrometer Internal and external blackbody calibration targets. Instrument put in “stand down” mode on sol 2257 after failing to respond to commands. Instrument Deployment Device (IDD)-Mounted In-Situ Package APXS: Alpha Particle X- 244Cm alpha particle sources, and x-ray detectors, 3.8 cm FOV. Ray Spectrometer MB: Mössbauer 57Fe spectrometer in backscatter mode; 57Co/Rh source and Si-PIN diode Spectrometer detectors; field of view approximately 1.5 cm. MI: Microscopic Imager 31 µm/pixel monochromatic imager (1024x1024) with 2 mm depth of field. RAT: Rock Abrasion Tool capable of brushing surfaces and grinding 5 mm deep by 4.5 cm wide Tool surface on rocks.

Engineering Cameras Navigation Cameras Mast-mounted panchromatic stereoscopic imaging system with 0.77 mrad (Navcam) IFOV; 45 deg FOV, and 20 cm stereo baseline separation. Hazard Avoidance Front and rear-looking panchromatic stereoscopic imaging systems with 2 Cameras (Hazcam) mrad IFOV; 123 deg FOV, 10 cm stereo baseline separation. 1181

1182

48

1183 Table 2 – Major activities for Opportunity organized by Sol. RS=remote sensing; 1184 MEX=Mars Express; AEGIS was an experiment focused on automatic rock detection. 1185 Other acronyms defined in Table 1. Earth Date Sol Activity Site 7/1/05-7/4/05 511-514 Leave “Purgatory” ripple; RS 55 7/5/05-7/7/05 515-517 Drive east towards “Erebus Crater”; RS 55 7/8/05-7/9/05 518-519 RS; recharge batteries 56 7/10/05-7/14/05 520-524 Drive east towards “Erebus Crater”, first use of combined 56 short segments of blind driving with small slip check segments; RS 7/16/05-8/5/05 525-545 RS; Right front steering actuator diagnostic test; Recharge; 56-57 Continue drive east toward “Erebus Crater” 8/6/05-8/23/05 546-562 Cobble field: IDD “OneScoop,” “Arkansas” cobble, 58 “Perseverance” cobble, “Reiner_Gamma” soil target, “Fruit_Basket” outcrop, and “Lemon_Rind” and “Strawberry” targets 8/24/05-9/3/05 563-573 Anomaly and recovery; RS 59 9/4/05-9/7/05 574-577 RS 58 9/8/05-9/11/05 578-581 Continue drive east toward “Erebus Crater”; RS 59 9/12/05-9/13/05 582-583 Arrive “Erebus Highway”, Continue drive east toward 60 “Erebus Crater” 9/12/05-9/21/05 584-591 Continue drive east toward “Erebus Crater; RS 60 9/23/05-9/26/05 592-595 Arrive “Erebus Crater”; “South Shetland” Feature: 62 Approach and IDD “Deception” target 9/27/05-9/29/05 596-598 Warm Reboot Anomaly, Stand Down, and Recover 62 9/30/05-10/1/05 599-600 RS, 360 degree Panorama 62 10/2/05-10/5/05 601-604 Drive northwest around “Erebus Crater”; RS 62 10/6/05 605 Backward drive out of ripple to outcrop 62 10/7/05-10/10/05 606-609 Drive westward around “Erebus Crater”; RS 62 10/11/05- 610-611 Spacecraft reset; Anomaly and recovery -- 10/12/05 10/13/05 612 Runout -- 10/14/05- 613-630 Continue drive westward around “Erebus Crater”; RS 62 10/31/05 11/2/05-11/9/05 631-638 Arrive “Olympia” outcrop: Approach and IDD 64 “Kalavrita” and “Ziakas” targets 11/10/05- 639-644 Approach, IDD, and RS “Antistasi” cobble 64 11/15/05 11/16/05- 645-646 RS 64 11/17/05 11/18/05- 647-649 RS; IDD Composition and Calibration Target 64 11/20/05 11/21/05- 650-653 RS; Drive 64 11/24/05 11/25/05- 654-656 IDD unstow failure 64

49

11/27/05 11/28/05- 657-659 RS 64 11/30/05 12/1/05-12/8/05 660-667 RS; IDD diagnostics 64 12/9/05-12/11/05 668-669 RS; Atmospheric observations 64 12/12/05 670 Atmospheric RS; Coordinated photometry campaign with 64 MEX 12/13/05- 671-674 RS; Atmospheric observations, IDD successfully un- 64 12/16/05 stowed 12/17/05- 675-678 IDD “Williams” target 64 12/20/05 12/21/05- 679-685 IDD “Ted” target 64 12/27/05 12/28/05-1/1/06 686-690 Continue IDD “Ted” target, IDD “Hunt” 64 1/2/06-1/7/06 691-696 Continue IDD “Ted” target 64 1/8/06 697 RS 64 1/10/06-1/12/06 698-701 “Martian Tai Chi”; Atmospheric and targeted RS 64 1/13/06-1/15/06 702-704 RS; unsuccessful IDD unstow 64 1/16/06-1/18/06 705-706 Coordinated observations with MEX 64 1/19/06 707 Successful bump 64 1/20/06-1/21/06 708-709 “Olympia” Outcrop, “Lower Overgaard” feature: IDD 64 “Scotch” target 1/22/06-1/23/06 710-711 Coordinated observations with MEX 64 1/24/06-1/26/06 712-714 Continue “Olympia” Outcrop, “Lower Overgaard” feature: 64 IDD “Scotch” target 1/27/06-1/28/06 715-716 “Olympia” Outcrop, “Overgaard” feature: IDD 64 “Branchwater” and “Bourbon” targets 1/29/06-1/30/06 717-718 RS 64 1/31/06-2/4/06 719-723 “Olympia” Outcrop, “Overgaard” feature: IDD 64 “Don_Giovani,” “Salzburg,” and “Nachtmusik” targets 2/5/06-2/6/06 724-725 Bump to “Roosevelt” 64 2/8/06-2/12/06 726-730 “Olympia” Outcrop, “Roosevelt” feature: IDD “Rough 64 Rider” and “Fala” targets 2/13/06-2/14/06 731-733 “Olympia” Outcrop, “Bellemont” feature: IDD “Vicos,” 64 “Tara,” “Chaco,” and “Verdun” targets 2/15/06-2/16/06 734-735 IDD stall; RS; short IDD diagnostic activity 64 2/17/06-2/20/06 736-739 Runout; Atmospheric Remote Science and Photometry 64 2/21/06-3/2/06 740-748 Drive toward and along “Payson” outcrop; RS 64-65 3/3/06-3/4/06 749-750 “Payson” outcrop: RS 64 3/5/06-3/12/06 751-758 Continue drive toward and along “Payson” outcrop; RS 64-65 3/13/06 759 Recharge; Atmospheric observations 65 3/14/06-3/16/06 760-762 Drive south toward “Victoria Crater”; RS 65-76 3/17/06 763 Atmospheric observations 65 3/18/06-3/21/06 764-767 Continue drive south toward “Victoria Crater”; RS 65-76 3/22/06-3/24/06 768-770 Odyssey safe mode; Limited downlink capability 66

50

3/25/06-3/26/06 771-772 Atmospheric observations; RS 66 3/27/06-3/30/06 773-776 Continue drive south toward “Victoria Crater”; RS 65-76 3/31/06-4/3/06 777-779 Recharge; RS 67 4/4/06-4/14/06 780-790 Continue drive south toward “Victoria Crater”; RS 65-76 4/15/06 791 IDD “Buffalo Springs” outcrop; RS 68 4/16/06-4/25/06 792-801 Continue drive south toward “Victoria Crater”; RS 65-76 4/26/06-4/27/06 802-803 Short drive to potential IDD target outcrop 69 4/28/06-4/30/06 804-806 IDD “Brookville” target 69 5/1/06-5/9/06 807-815 Continue drive south toward “Victoria Crater”; RS 65-76 5/11/06 816 Atmospheric observations 70 5/12/06 817 Continue drive south toward “Victoria Crater”; RS 65-76 5/13/06-5/15/06 818-820 IDD “Cheyenne” outcrop 70 5/16/06-5/19/06 821-824 Continue drive south toward “Victoria Crater”; RS 65-76 5/20/06-5/22/06 825-827 IDD “Alamogordo Creek” soil target 71 5/23/06-5/27/06 828-832 Continue drive south toward “Victoria Crater”; RS 65-76 5/28/06-6/6/06 833-842 Opportunity embedded in “Jammerbugt” ripple; Extraction 71 6/7/06-6/8/06 843-844 Continue drive south toward “Victoria Crater”; RS 65-76 6/9/06 845 Targeted RS 72 6/10/06-6/15/06 846-851 Continue drive south toward “Victoria Crater”; RS; 72 Atmospheric observations 6/16/09 852 Begin new flight software uplink 72 6/18/06-6/24/06 853-859 RS 72 6/25/06-7/7/06 860-872 Continue drive south toward “Victoria Crater”; RS 65-76 7/8/06-7/13/06 873-878 Drive toward “Beagle Crater” 73-74 7/14/06-7/16/06 879-881 IDD “Westport” disturbed soil target and “Fort Graham” 74 undisturbed soil target; RS “Dallas” disturbed soil target and “Waco” outcrop 7/17/06-7/19/06 882-884 Runout; RS; Drive toward “Beagle Highway” 74 7/20/06-7/26/06 885-890 Approach, scuff, and IDD “Jesse Chisolm” target; IDD 74 “Joseph McCoy” cobble, “Haiwassee” cobble 7/27/06 891 Approach and scuff soil target; RS 74 7/28/06 892 RS 74 7/29/06-8/1/06 893-896 IDD and RS “Baltra” outcrop pavement 74 8/2/06-8/6/06 897-901 Recharge; Drive to rim of “Beagle”; RS 74 8/7/06-8/9/06 902-904 Spacecraft fault and recovery 74 8/10/06-8/14/06 905-909 RS 74 8/15/06-8/16/06 910-911 IDD “Isabela” and “Marchena” ripple banding targets 74 8/17/06-8/23/06 912-918 Continue drive south toward “Victoria Crater”; RS 65-76 8/24/06 919 IDD shoulder azimuth joint stalled; Diagnostic 75 measurements; scuff soil 8/25/06-8/27/06 920-922 IDD stall 75 8/28/06-9/2/06 923-927 IDD diagnostics 75 9/3/06 928 Sol 919 scuff: IDD “Powell” and “Powell’s Brother” 75 targets 9/4/06 929 Drive toward “Emma Dean” crater 75

51

9/5/06-9/10/06 930-935 RS 75 9/11/06-9/16/06 936-941 Approach, IDD, and RS “Cape Faraday” possible ejecta 75 target 9/17/06-9/22/06 942-947 Continue drive south toward “Victoria Crater”; RS 65-76 9/23/06 948 Mobility tests 76 9/24/06-9/27/06 949-952 Continue drive south toward “Victoria Crater”; RS 65-76 9/28/06-8/29/06 953-954 Targeted RS: “Duck Bay” 76 9/30/06-10/4/06 955-959 Drive toward “Cape Verde” promontory; RS 76 10/5/06 960 RS 76 10/6/06-10/10/06 961-964 IDD “Fogo” target 76 10/11/06- 965-967 RS; Recharge 76 10/13/06 10/14/06- 968-969 Make room in flash for conjunction data 76 10/15/06 10/16/06- 970-984 Solar Conjunction; “Cape Verde” Panorama, IDD “Cha” 76 10/30/06 target; Cape Verde Pan 10/31/06-11/6/06 985-991 Continue “Cape Verde” Panorama 76 11/7/06-11/18/06 992-1002 Drive to “Cape St. Mary” promontory; RS 76 11/19/06- 1003-1004 Untargeted RS 76 11/20/06 11/21/06- 1005-1006 MGS contact attempts; RS “Cape Verde”; Targeted RS 76 11/22/06 11/23/06- 1007-1008 Targeted RS 76 11/24/06 11/25/06- 1009-1012 Drive toward “Bottomless Bay”; RS 76-77 11/28/06 11/29/06 1013 MRO coordinated observations; RS 76 11/30/06 1014 Drive toward “Bottomless Bay”; RS 76 12/1/06 1015 RS 77 12/2/06 1016 Continue drive toward “Bottomless Bay”; RS; IDD 77 autoplace checkout 12/3/06 1017 Atmospheric RS 77 12/4/06 1018 Ground survey; APXS argon density measurement 77 12/5/06-12/6/06 1019-1020 RS “Bottomless Bay”; Atmospheric RS 77 12/7/06-12/20/06 1021-1034 Drive closer to “Bottomless Bay”; RS; IDD autoplace 77 checkout 12/22/06- 1035-1036 IDD “Rio de Jeneiro” target 77 12/23/06 12/24/06 1037 Phoenix demo 77, 78 12/25/06 1038 Continue IDD “Rio de Jeneiro” target 77 12/26/06 1039 Drive toward “Bay of Toil”; Atmospheric RS 77-78 12/27/06 1040 APXS atmosphere 77, 78 12/28/06-1/9/07 1041-1053 Drive to, IDD, and RS “Santa Catarina” cobble 78 1/10/07 1054 Atmospheric RS 78 1/11/07-1/12/07 1055-1056 RS 78

52

1/13/07 1057 APXS argon measurement; Atmospheric RS 78 1/14/07 1058 Continue drive toward “Bay of Toil” 77, 78 1/15/07 1059 RS 78 1/16/07-1/17/07 1060-1061 “Bay of Toil” long baseline stereo RS 78 1/18/07 1062 RS cobbles, image Comet McNaught 78 1/19/07 1063 APXS argon measurement; RS 78 1/20/07-1/22/07 1064-1066 Drive toward “Cape Desire”; RS; tests to solve visual 78 odometry “picket fence” problem 1/23/07-1/25/07 1067-1069 Drive toward tip of “Cape Desire” 78 1/26/07 1070 IDD and RS 78 1/27/07 1071 Continue drive toward tip of “Cape Desire”; RS 78 1/29/07 1072 RS magnets and atmosphere 78 1/30/07-1/31/07 1073-1074 Long baseline stereo RS “Cabo Corrientes” 78 2/1/07-2/3/07 1075-1077 Approach and RS “Cabo Anonimo” 78 2/4/07-2/10/07 1078-1084 Drive toward “Cabo Corrientes”; RS 79 2/11/07-2/16/07 1085-1090 Drive to position to image “Cape Desire”; Atmospheric RS 79 2/17/07-2/23/07 1091-1097 RS “Cape Desire,” “ExtremaDura” outcrop and “Cape of 79 Good Hope” (“Madrid” and “Alava” outcrops) 2/24/07-2/28/07 1098-1102 Drive to “Cape of Good Hope”; RS 79-80 3/1/07 1103 IDD diagnostic 79 3/2/07-3/5/07 1104-1107 Continue drive to “Cape of Good Hope”; RS 79-80 3/7/07-3/10/07 1108-1111 Drive toward “Valley Without Peril”; RS “Cape St. 80 Vincent” 3/11/07 1112 RAT grind test 80 3/12/07-3/14/07 1113-1115 Continue drive toward “Valley Without Peril”; RS “Cape 80 St. Vincent” 3/15/07-3/19/07 1116-1120 Race condition fault; Recover; Rest sols -- 3/20/07-3/26/07 1121-1127 Continue drive toward “Valley Without Peril”; RS “Cape 80 St. Vincent” 3/27/07 1128 RAT grind diagnostics 81 3/28/07-4/1/07 1129-1133 Continue drive toward “Valley Without Peril”; RS “Cape 80 St. Vincent” 4/2/07-4/4/07 1134-1136 Approach and IDD “Salamanca” and “Sevilla” soil targets 81 (wind streaks); RS 4/5/07-4/6/07 1137-1138 East and west photometry 81 4/7/07-4/9/07 1139-1141 IDD and RS dark streak; RS 81 4/10/07-4/11/07 1142-1143 Drive to second location in dark streak; IDD 81 4/13/07-4/19/07 1144-1150 Drive to “Alicante” dark streak soil target, IDD, and RS; 81 RS 4/20/07-4/21/07 1151-1152 Atmospheric RS 81 4/22/07-4/25/07 1153-1156 Drive to “Tierra del Fuego”; Long-baseline stereo of “Cape 81 St. Vincent”; RS 4/26/07 1157 Drive to “Granada” 81 4/27/07-4/28/07 1158-1159 Atmospheric RS 82 4/29/07 1160 RS; D* checkout 82

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4/30/07 1161 RS “Malaga” and “Granada” 82 5/1/07-5/3/07 1162-1164 Drive toward “Cape of Good Hope”; RS 82 5/4/07 1165 Atmospheric RS 82 5/5/07-5/8/07 1166-1169 RAT touch test on “Viva La Rata”; IDD and RS 82 5/9/07 1170 IDD diagnostics; Drive to “Madrid” 82 5/10/07 1171 Drive to “Pedriza” cobble 82 5/11/07 1172 Soil thermal inertia experiment 82 5/12/07-5/13/07 1173-1174 Drive; Atmospheric RS 82 5/14/07 1175 Bump to “Cercedilla”; RS 82 5/15/07-5/23/07 1176-1183 “Cercedilla” feature: IDD “Penota” target; RS 82 5/24/07-6/13/07 1184-1204 Drive toward “Cape Verde”; RS; D* checkout, Visual 83, 84, Target Tracking checkout 85 6/14/07-6/22/07 1205-1213 Long baseline stereo RS 85 6/23/07-6/29/07 1214-1219 Drive; RS 85 6/30/07-8/20/07 1220-1270 Dust storm; Atmospheric dust monitoring; Limited activity 85 to conserve power 8/21/07-9/3/07 1271-1284 Drive toward rim of “Victoria Crater”; Self Portrait; RS 85-86 9/4/07-9/8/07 1285-1288 Drive toward ingress point; RS; Diagnostics 86 9/9/07 1289 Drive to “Paulo’s Perch”; RS 86 9/10/07 1290 Atmospheric RS 86 9/11/07 1291 Toe dip (drive into and out of “Victoria Crater”) 86 9/12/07-9/13/07 1292-1293 Drive into Victoria Crater; RS 86 9/14/07-9/17/07 1294-1297 Odyssey safe mode; RS 86 9/18/07 1298 Odyssey safe mode; Drive toward “Alpha Layer” 86 9/19/07-9/21/07 1299-1301 Atmospheric RS 86 9/22/07-9/25/07 1302-1305 Approach “Alpha Layer”; RS 86 9/26/07 1306 RS 87 9/27/07-10/10/07 1307-1320 IDD “Steno” layer; RS 86-87 10/11/07 1321 Drive to second IDD target on “Steno” layer 87 10/12/07- 1322-1327 “Steno” layer: IDD and RS “Hall” target 87 10/18/07 10/19/07- 1328-1329 Drive toward “Smith” layer; RS 87 10/20/07 10/21/07- 1330-1331 Atmospheric RS 87 10/22/07 10/23/07- 1332-1358 IDD “Smith” rock outcrop; RS “Sharp” sequence of fine 87 11/18/07 layers; Targeted RS; RAT diagnostics 11/19/07- 1359-1361 IDD “Smith2” rock outcrop; RAT diagnostics 87 11/22/07 11/23/07- 1362-1379 Continue IDD “Smith2” rock outcrop 87 12/10/06 12/11/07- 1380-1381 Atmospheric RS 87 12/12/07 12/13/07 1382 Drive to “Lyell” layer, “Newell” target; RS 87 12/14/07 1383 Atmospheric RS 88

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12/15/07- 1384-1394 IDD “Lyell_1” target; RS 88 12/25/07 12/26/07 1395 IDD “Lyell_2” target; RS 88 12/27/07-1/2/08 1396-1401 IDD “Lyell_3” target; RS 88 1/3/08 1402 Drive to “Smith-Lyell” contact; RS 88 1/4/08 1403 RS 88 1/5/08 1404 IDD “Smith Lyell” contact; RS 88 1/6/08-1/7/08 1405-1406 IDD “Lyell_4” target; RS 88 1/8/08-1/11/08 1407-1410 IDD diagnostics; IDD “Smith_3” 88 1/12/08-1/16/08 1411-1415 IDD “Lyell” side of “Smith-Lyell” contact; RS 88 1/17/08-1/19/08 1416-1418 Drive to “Buckland” outcrop 88 1/20/08-1/21/08 1419-1420 Atmospheric RS 88 1/22/08-2/8/08 1421-1437 IDD “Buckland” outcrop; RS 88 2/9/08-2/21/08 1438-1450 Drive to “Gilbert” outcrop; RS; Scuff “Gilbert” outcrop; 88 IDD “Lyell-Exeter” target 2/22/08 1451 APXS argon; RS 88 2/23/08-2/25/08 1452-1454 IDD filter and capture magnets; RS 88 2/26/08-2/27/08 1455-1456 IDD “Gilbert A” 88 2/28/09 1457 “Gilbert” outcrop: IDD “Dorsal” target 88-89 2/29/08-3/2/08 1458-1460 DSN transmitter failure; Runout -- 3/3/08-3/5/08 1461-1463 “Gilbert” outcrop: IDD “Dorsal” target 88-89 3/6/08-3/10/08 1464-1468 “Gilbert” location: IDD “Dorsal Tail” target 89 3/11/08-3/14/08 1469-1471 “Gilbert” location: IDD “Dorsal New” target 89 3/15/08-3/16/08 1472-1473 Supperres rimshot; Atmospheric RS 89 3/17/08 1474 Atmospheric RS 89 3/18/08-3/26/08 1475-1483 IDD “Gilbert_RAT” target; RS 89 3/27/08-4/14/08 1484-1502 Drive toward “Cape Verde”; RS 89-90 4/15/08-5/28/08 1503-1544 IDD diagnostics; RS 89 5/29/08-5/30/08 1545-1546 RS “Garrels” panorama and “Williams” target; 89 Atmospheric RS 5/31/08-6/14/08 1547-1561 Continue drive toward “Cape Verde”; RS 89-90 6/15/08 1562 Scuff and RS soil 90 6/16/08-6/22/08 1563-1569 Continue drive toward “Cape Verde”; RS 89-90 6/23/08-7/5/08 1570-1581 “Cape Verde” panorama; RAT diagnostics 90 7/6/08-7/24/08 1582-1600 Continue drive toward “Cape Verde”; RS; RAT calibration 89-90 7/25/08 1601 Atmospheric RS 90 7/26/08-7/28/08 1602-1604 Drive (left front wheel) diagnostics 90 7/29/08-7/31/08 1605-1607 RS “Eugene Smith,” “Siever,” and “McKee” targets and 90 “Cape Verde”; Atmospheric RS 8/1/08-8/3/08 1608-1610 Safe mode 90 8/4/08-8/16/08 1611-1622 Exit “Victoria Crater;” RS 90 8/17/08 1623 RS “Logan” rock weathering target 90 8/18/08-8/19/08 1624-1625 Continue exit “Victoria Crater”; RS 90 8/20/08 1626 RS “Jin” cobble 90 8/21/08 1627 Continue exit “Victoria Crater”; RS 90

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8/22/08 1628 RS “Barghorn” target 90 8/23/08-8/24/08 1629-1630 Continue exit “Victoria Crater”; RS 90 8/25/08 1631 RS “Dawson” and “Eugster” targets 90 8/26/08 1632 Continue exit “Victoria Crater”; RS 90 8/27/08 1633 RS 90 8/28/08-8/29/08 1634-1635 Atmospheric RS 90 8/30/08 1636 RS tracks, ripple, and “Isle Royale” target 90 8/31/08-9/1/08 1637-1638 Atmospheric RS 90 9/2/08-9/3/08 1639-1640 RS “Bright Patch Two” target 90 9/4/08 1641 Bump to “Bright Patch” 90 9/5/08-9/7/08 1642-1644 IDD “Victoria” rim sand dune 90 9/8/08-9/10/08 1645-1647 IDD “Victoria” ripple soil 90 9/11/08-9/18/08 1648-1654 Drive toward lee side of ripple; Atmospheric RS 90 9/19/08-9/22/08 1655-1658 Atmospheric RS 90 9/23/08-9/24/08 1659-1660 RS; APXS Argon 90 9/25/08 1661 Drive by “Sputnik Crater” 90 9/26/08-10/9/08 1662-1675 Drive toward “Cape Victory” and “Cape Agulhas” on 90-91 “Victoria Crater”; RS “Cape Pillar” and “Cape Victory” 10/10/08 1676 RS “Savu Sea” bedrock 91 10/11/08- 1677-1679 Continue drive toward “Cape Victory” and “Cape 90-91 10/13/08 Agulhas” on “Victoria Crater”; RS “Cape Pillar” and “Cape Victory” 10/14/08 1680 MTES shake 91 10/15/08 1681 Continue drive toward “Cape Victory” and “Cape 90-91 Agulhas” on “Victoria Crater”; RS “Cape Pillar” and “Cape Victory” 10/16/08- 1682-1683 Drive toward “Endeavour Crater”; RS 91 10/17/08 10/18/08- 1684-1713 Continue drive toward “Endeavour Crater”; RS; APXS 91-92 11/17/08 Argon 11/18/08- 1714-1718 Arrive at solar conjunction location; IDD “Santorini” 94 11/22/08 cobble 11/23/08- 1719-1721 “Santorini” Panorama; RS “Corfu” outcrop patch 94 11/25/08 11/26/08- 1722-1723 Runout 94 11/27/07 11/28/08- 1724-1740 Solar Conjunction; IDD “Santorini” cobble 94 12/15/08 12/16/08- 1741-1742 Delete data products; Atmospheric RS; IDD “Santorini” 94 12/17/08 cobble 12/18/08- 1743-1747 IDD and RS “Santorini” cobble 94 12/22/08 12/23/08 1748 Approach “Crete” bedrock and soil targets 94

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12/24/08- 1749-1750 Atmospheric RS 94 12/25/08

12/26/08- 1751-1753 IDD “Crete” bedrock target 94 12/28/08 12/29/08 1754 “Crete” bedrock: IDD “Candia” rock target 94 12/30/08-1/2/09 1755-1758 “Crete:” IDD “Minos” soil target 94 1/3/09-1/5/09 1759-1761 Atmospheric RS 94 1/6/09-1/12/09 1762-1767 RAT diagnostics; Atmospheric RS 94 1/13/09 1768 MTES shake test 94 1/14/09 1769 RS; APXS Argon 94 1/15/09 1770 Drive toward “Ranger Crater” 94 1/16/09 1771 MTES shake test 94 1/17/09-1/20/09 1772-1775 Atmospheric RS 94 1/21/09 1776 Approach “Ranger Crater” 94 1/22/09-1/24/09 1777-1779 RS “Ranger Crater”; Atmospheric RS 95 1/25/09-1/26/09 1780-1781 Drive south; RS; APXS Argon 95 1/27/09 1782 Drive by “Surveyor Crater”; RS 95 1/28/09 1783 RS; APXS Argon 95 1/39/09 1784 RS ripple offset 95 1/30/09-2/1/09 1785-1787 Drive; RS; APXS Argon 95 2/2/09-2/4/09 1788-1790 PMA fault diagnostics 96 2/5/09-2/14/09 1791-1799 Drive toward “Endeavour Crater”; RS; APXS Argon 97 2/15/09 1800 Right front wheel diagnostic drive 98 2/16/09 1801 Automatic AutoNav Map Load Test 98 2/17/09-2/23/09 1802-1808 Continue drive toward “Endeavour Crater”; RS; APXS 98 Argon 2/24/09 1809 “Marsquake” observation 98 2/25/09 1810 RS; APXS Argon 98 2/26/09 1811 FSW R9.3 build 98 2/27/09-3/4/09 1812-1817 Continue drive toward “Endeavour Crater”; RS; APXS 98 Argon 3/5/09 1818 RS cobble 98 3/6/09-3/9/09 1819-1822 RS; APXS Argon 99 3/10/09 1823 Bump to “Resolution Crater”; RS 99 3/11/09 1824 Approach “Cook_Islands” outcrop 99 3/12/09-3/18/09 1825-1831 Approach, IDD, and RS “Cook Islands” cobble patch; RS 99 “Lost” cobble; Atmospheric RS 3/19/09-4/6/09 1832-1849 “Cook Islands” cobble patch: IDD “Penrhyn” and 99 “Takutea” targets 4/7/09-4/9/09 1850-1852 Drive to and RS “Adventure” crater 99 4/10/09 1853 Atmospheric RS 99 4/11/09 1854 Drive to “Discovery Crater” 99 4/12/09 1855 Atmospheric RS 99 4/13/09-4/15/09 1856-1858 Drive to and RS “Pembroke Crater” 99

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4/16/09-5/2/09 1859-1874 Continue drive toward “Endeavour Crater”; RS; APXS 99-100 Argon 5/3/09 1875 “Marsquake” observation 100 5/4/09 1876 RS 100 5/5/09-5/11/09 1877-1883 Bump to pebble patch; IDD and RS “Tilos,” “Kos,” and 100 “Rhodes” pebbles 5/12/09-5/18/09 1884-1890 Drive to and IDD “Kasos” pebble 100 5/19/09-5/26/09 1891-1898 Continue drive toward “Endeavour Crater”; RS; APXS 100- Argon 101 5/27/09 1899 MI sky flats test 101 5/28/09-6/10/09 1900-1912 Continue drive toward “Endeavour Crater”; RS; APXS 102 Argon 6/11/09-6/15/09 1913-1917 Atmospheric RS 103 6/16/09-6/17/09 1918-1919 IDD “Ios” target 103 6/18/09-6/24/09 1920-1926 Drive to and IDD “Tinos” target; RS “Donousa,” “Dryma,” 103 “Naxos,” and “Mykonos” targets 6/25/09-6/28/09 1927-1930 Continue drive toward “Endeavour Crater”; RS; APXS 103 Argon 6/29/09-7/9/09 1931-1941 IDD “Little Beach” and “Absecon” targets 103 7/10/09-7/16/09 1942-1947 Continue drive toward “Endeavour Crater”; RS 103- 104 7/17/09 1948 Marsquake observation; RS 104 7/18/09 1949 RS; APXS Argon 104 7/19/09 1950 Drive to “Kaiko” and “Nereus” craters; RS 104 7/20/09 1951 RS 104 7/21/09-7/30/09 1952-1961 Drive toward “Block Island” meteorite; IDD and RS 104- 105 7/31/09-8/10/09 1962-1972 “Block Island” meteorite: IDD and RS “New Shoreham,” 105 “Clayhead Swamp,” “Springhouse Icepond,” “Middle Pond” 8/11/09-8/12/09 1973-1974 Bump to “Vail Beach” soil pebbles; IDD “Vail Beach” 105 8/13/09-8/31/09 1975-1992 Bump to “Siah’s Swamp” and “Veteran’s Park” targets: 105 IDD and RS; IDD and RS “Siah’s Swamp2” and “Fresh Pond”; RS “Block Island” meteorite 9/1/09-9/2/09 1993-1994 Runout 105 9/3/09-9/4/09 1995-1996 RS 105 9/5/09-9/11/09 1997-2003 Drive around and image “Block Island” meteorite (6 105 positions), RS 9/12/09-9/18/09 2004-2010 Continue drive toward “Endeavour Crater”; RS; APXS 105 Argon 9/19/09 2011 RS “Nautilus” crater 106 9/20/09-9/21/09 2012-2013 Continue drive toward “Endeavour Crater”; RS 106 9/22/09-9/24/09 2014-2015 RS Gjoa crater 106 9/25/09 2016 IDD “Limnos” target 106 9/26/09 2017 Continue drive toward “Endeavour Crater”; RS 106

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9/27/09 2018 “Marsquake” observation 106 9/28/09-9/30/09 2019-2021 Continue drive toward “Endeavour Crater”; RS; APXS 106- Argon 107 10/1/09 2022 RS “Shelter Island” meteorite 107 10/2/09 2023 RS; APXS Argon 107 10/3/09-10/12/09 2024-2033 Approach, IDD, and RS “Shelter Island” meteorite: 107 “Dering Harbor” target 10/13/09- 2034-2038 Drive to “Mackinac” meteorite; RS 107 10/17/09 10/18/09- 2039-2043 RS; APXS Argon 107 10/22/09 10/23/09 2044 DSN station down, Runout 108 10/24/09- 2045-2046 Continue drive toward “Endeavour Crater”; RS 108 10/25/09 10/26/09 2047 RS “Trinidad” Crater 108 10/27/09-11/3/09 2048-2054 Continue drive toward “Endeavour Crater”; RS; APXS 108 Argon 11/4/09-11/12/09 2055-2063 Drive toward “Marquette Island” rock; RS 109 11/13/09 2064 RS 109 11/14/09- 2065-2071 “Marquette Island” rock: IDD “Peck Bay” target 109 11/20/09 11/21/09-12/4/09 2072-2085 “Marquette Island” rock: IDD “Islington Bay” target 109 12/5/09-12/7/09 2086-2088 Drive toward “Marquette Island’s” unseen side 109 12/9/09-12/12/09 2089-2092 “Marquette Island” rock: IDD “Loon Lake” target 109 12/13/09- 2093-2096 RS 109 12/16/09 12/17/09-1/10/10 2097-2121 “Marquette Island” rock: IDD “Peck Bay” target 109 1/11/10-1/13/10 2122-2124 Continue drive toward “Endeavour Crater”; RS 109 1/15/10-1/19/10 2125-2129 Drive toward “Concepciòn” Crater 109- 111 1/20/10 2130 AEGIS checkout 110 1/21/10-1/28/10 2131-2138 Continue drive toward “Concepciòn” Crater 109- 111 1/29/10 2139 RS 111 1/30/10 2140 “Concepciòn” panorama 111 1/31/10 2141 IDD “Mahany Island” target 111 2/1/10 2142 “Concepciòn” panorama 111 2/2/10-2/3/10 2143-2144 IDD “Loboc River” target 111 2/4/10-2/7/10 2145-2148 Drive toward “Concepciòn Crater” 111 2/8/10 2149 Bump toward “Chocolate Hills” 111 2/9/10-2/10/10 2150-2151 “Chocolate Hills” rock: IDD “Aloya” dark material 111 2/11/10 2152 Bump around “Chocolate Hills” 111 2/12/10-2/14/10 2153-2155 “Chocolate Hills” rock: IDD “Arogo” target 111 2/15/10 2156 RS 111 2/16/10-2/19/10 2157-2160 “Chocolate Hills” rock: IDD “Tears” target, IDD “Dano” 111

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target 2/20/10-3/3/10 2161-2171 Drive around “Concepciòn Crater”; RS 111 3/4/10 2172 AEGIS checkout 111 3/5/10-3/8/10 2173-2176 Continue drive around “Concepciòn Crater”; RS 111 3/9/10 2177 Return to “Pink Path” and drive to “Endeavour Crater” 111 3/10/10-3/27/10 2178-2195 Continue drive toward “Endeavour Crater”; RS 111- 112 3/28/10-3/30/10 2196-2198 RS “San Antonio West” and “San Antonio East” craters 114 4/1/10-4/12/10 2199-2210 Continue drive toward “Endeavour Crater”; RS 114 4/13/10 2211 Dune crossing, soil mechanics experiment 115 4/14/10-4/22/10 2212-2220 Continue drive toward “Endeavour Crater”; RS 115 4/23/10 2221 AEGIS watch 115 4/24/10-4/25/10 2222-2223 RS 116 4/26/10 2224 IDD “Ocean Watch” undisturbed soil target 116 4/27/10-4/29/10 2225-2227 Continue drive toward “Endeavour Crater”; RS 116 4/30/10-5/2/10 2228-2230 Drive toward “Newfoundland” rock; RS 116 5/3/10-5/13/10 2231-2240 Continue drive towards “Endeavour Crater”, drive to “Lily 116 Pad”; Argon APXS, drive to “Lily Pad”; RS 5/14/10-5/19/10 2241-2246 RS; MarsQuake Experiment; Drive south 116- 117 5/20/10-5/26/10 2247-2253 AEGIS experiment; Drive east; RS 117 5/27/10-5/29/10 2254-2256 Drive; RS 117 5/30/10-5/31/10 2257-2258 Get fine attitude; recharge; Mini-TES in stand down mode 117- 118 6/1/10-6/3/10 2259-2261 PMA diagnostics 118 6/4/10-6/6/10 2262-2264 Hazcam; Argon APXS; Recharge 118 6/7/10 2265 PMA diagnostics 118 6/8/10-6/9/10 2266-2267 RS; Recovery QFA and post-drive imaging 118 6/10/10-6/17/10 2268-2274 RS; Recharge; Drive east towards Endeavour 118 6/18/10-6/19/10 2275-2276 RS; Drive south 118 6/20/10-6/21/10 2277-2278 Argon APXS; AEGIS experiment 119 6/22/10-6/30/10 2279-2287 Drive east-southeast, drive northward, drive east; RS 120 7/1/10-7/5/10 2288-2292 Drive eastward; RS; AEGIS experiment 120 7/6/10-7/7/10 2293-2294 Drive east toward “Endeavour Crater”; RS 120 7/8/10-7/9/10 2295-2296 Drive; RS 120 7/10/10 2297 IDD “Juneau_Road_Cut” target, IDD “Juneau” target 120 7/11/10 2298 RS 120 7/12/10-7/13/10 2299-2300 Drive east-southeast toward gravel pile; RS 120- 121 1186 1187

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Table 3: Overview of cobbles discussed in this paper in order of discovery. Measurementsd Namea Solb Classification and Referencec Location APXS MB MI stacks close to the rim of Eagle Bounce Rock 63 basaltic shergottite [1, 2] 2U, R 7U, R 10U,4R crater north-western rim of Lion Stone 105 outcrop fragment [2, 3] U, R U, R 2U, 5R Endurance crater southern rim of Endurance Barberton 121 dark toned cobble (Barberton group) [2, 3, 4, 5] U U 2U crater plains; close to the Heat Heat Shield Rock 347 iron meteorite [2, 4, 6, 7] U, B U, B 6U, 4B Shield Russett 381 outcrop fragment [2, 3] plains U U 2U Arkansas 551 dark toned cobble (Arkansas group) [2, 3] close to Erebus crater U U U Perseverance 554 dark toned cobble (Arkansas group) [2, 3] close to Erebus crater U n. a. U Antistasi 641 dark toned cobble (Arkansas group) [2, 3] close to Erebus crater U U 4U Jesse Chisholm area close to JosephMcCoy 886 dark toned cobble (Arkansas group) [2, 3] U U 4U Beagle crater Jesse Chisholm area close to Haiwassee 886 dark toned cobble (Arkansas group) [2, 3] U n. a. U Beagle crater Cobble field close to the rim Santa Catarina 1045 dark toned cobble (Barberton group) [2, 3, 4, 5] U U 5U of Victoria crater Santa Catarina cobble likely genetically related to Santa Catarina [4, Cobble field close to the rim 1045 n. a. n. a. n. a. field 8] of Victoria crater ~800 m south of Victoria Santorini 1741 dark toned cobble (Barberton group) [2, 3, 5] 2U U 3U crater ~1.5 km south of Victoria Kos 1879 dark toned cobble (Arkansas group) [2] U n. a. U crater ~1.5 km south of Victoria Tilos 1879 dark toned cobble (Arkansas group) [2] U n. a. U crater ~1.5 km south of Victoria Rhodes 1879 dark toned cobble (Arkansas group) [2] U n. a. U crater

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dark toned cobble (Barberton group) ~1.5 km south of Victoria Kasos 1886 U U 4U [2, 3, 5] crater ~4 km south-southwest of Block Island 1961 Iron meteorite [2, 4, 7] 6U 4U 26U Victoria crater ~4 km south-southwest of Vail Beach 1974 dark toned cobble (Arkansas group) [2, 3] U n. a. 5U Victoria crater Shelter Island 2022 Iron meteorite [4, 7] U n. a. 2U Mackinac Island 2034 Iron meteorite [4, 7] n. a. n. a. n. a. Marquette Island 2065 Martian mafic igneous ejecta block [9] 3U, R 3U, R 5U, 8B, 10R on the rim of Concepción Chocolate Hills 2150 impact-melt covered ejecta block U U 18U crater a Names are informal and not officially approved by the International Astronomical Union. b The sol indicates the beginning of investigations with IDD instruments. cReferences: [1] Zipfel et al. 2010. [2] Weitz et al., 2010. [3] Fleischer et al.2010a. [4] Schröder et al., 2008. [5] Schröder et al., 2010. [6] Connolly et al., 2006. [7] Ashley et al., 2010. [8] Ashley et al., 2009. [9] Mittlefehldt et al., 2010. d number of APXS, Mössbauer (MB) and MI measurements listed for undisturbed (U), brushed (B) and RAT-abraded (R) targets. Number is omitted if one measurement was made.

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